REG - Greatland Gold PLC - Havieron Resource and Reserve Update
03/03/2022 08:00
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RNS Number : 5140D Greatland Gold PLC 03 March 2022
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3 March 2022
THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION AS STIPULATED UNDER THE UK
MARKET ABUSE REGULATIONS. ON PUBLICATION OF THIS ANNOUNCEMENT VIA A
REGULATORY INFORMATION SERVICE, THIS INFORMATION IS CONSIDERED TO BE IN THE
PUBLIC DOMAIN.
Greatland Gold plc
("Greatland" or "the Company")
Updated Mineral Resource substantially increases Havieron Resource and Reserve
Mineral Resources (including Ore Reserves) increase to 5.5M oz Au and 218kt Cu
or 6.5M oz AuEq(1),
an increase of 2.1M oz AuEq(1) since the last Mineral Resource update
Probable Ore Reserves now stand at 2.4M oz Au and 109kt Cu or 2.9M oz
AuEq(1),
compared to the 1.7M oz AuEq(1) in the Initial Ore Reserve estimation
Initial Mineral Resource estimated in the Eastern Breccia
Updated Mineral Resource incorporates an additional 10 months of consistently
impressive drilling results since the February 2021 drilling cut-off used for
the last Mineral Resource update
Havieron Mineral Resource Update Highlights*
§ A 53% increase in total gold content to 5.5M oz Au (6.5M oz AuEq(1))
§ A 63% increase in Indicated Mineral Resource gold ounces to 3.1M oz Au
§ An Initial Inferred Mineral Resource estimated at the Eastern Breccia
§ Mineral Resources include 33Mt @ 3.28 g/t Au and 0.48% Cu (containing 3.5M
oz Au and 158kt Cu or 4.2M oz AuEq(1)) in the South East Crescent Zone
§ Update has been subject to a detailed analysis and review, independently
assessed by SRK Consulting and are reported in compliance with JORC (2012)
guidelines
Updated Mineral Resource estimate for the Havieron Deposit (100%)(#)
Classification Tonnage Grade Metal Content AuEq (1) ( )Metal
Mt Au (g/t) Cu (%) Au (M oz) Cu (kt) AuEq
(M oz)
Indicated 35 2.8 0.42 3.1 146 3.8
Inferred 57 1.3 0.13 2.4 72 2.7
Total Mineral Resource 92 1.9 0.24 5.5 218 6.5
(#) Results are reported to one (gold) and two (copper) significant figures to
reflect appropriate precision in the estimate, and this may cause some
apparent discrepancies in totals. Results represent 100% of the Mineral
Resource for Havieron. Mineral Resources in the Crescent are reported within a
A$80 NSR/t shell while Mineral Resources in the Breccias are reported within a
A$50 NSR/t shell. Resources are inclusive of Reserves.
* The Updated Mineral Resource Estimates assume selective mining of the South
East Crescent Zone and bulk extraction in the Breccias and are reported inside
A$80 or A$50 Net Smelter Return/t(2) ("NSR/t") shells respectively.
Havieron Ore Reserve Update Highlights
§ 50% increase in contained gold ounces to 2.4M oz Au (2.9M oz AuEq),
including an 86%(3) conversion of Indicated Mineral Resources to Probable Ore
Reserves
§ The conversion rate of the South East Crescent Zone reiterates the robust
nature of the South East Crescent Zone within the Havieron deposit while
providing confidence in the ongoing conversion of further South East Crescent
Zone material as drilling continues
§ Update has been subject to a detailed analysis and review, independently
assessed by SRK Consulting and are reported in compliance with JORC (2012)
guidelines
Updated Ore Reserve estimate tabulation for the Havieron Deposit (100%)^
Tonnage Grade Metal Content AuEq (1) Metal
Mt Au (g/t) Cu (%) Au (M oz) Cu (kt) AuEq (M oz)
Proved - - - - - -
Probable 25 3.0 0.44 2.4 109 2.9
Total Ore Reserve 25 3.0 0.44 2.4 109 2.9
^ Data is reported to one (gold) or two (copper) significant figures to
reflect appropriate precision in the estimate and this may cause some apparent
discrepancies in totals. Data represents 100% of the Ore Reserve for Havieron.
Ore Reserves are reported above a cut-off of A$95 NSR/t and reported within
mining shapes based on a sub-level open stoping mining method. All reported
metal was derived from the South East Crescent Zone only.
Greatland Gold plc (AIM:GGP), a leading mining development and exploration
company with a focus on precious and base metals, is pleased to provide an
independently assessed update on the Mineral Resources and Ore Reserves at the
Havieron gold-copper deposit in the Paterson region of Western Australia. The
update is based on increased drill density throughout the deposit with a
further 87 drill holes for 59,270m completed since the last Resources and
Reserves update published in the Pre-Feasibility Study ("Stage 1 PFS"), which
used drill data up to February 2021.
Havieron Growth
§ This Resource update is at a 'point in time', with a 2 December 2021
cut-off for drilling information used to inform the Mineral Resource Estimate
§ Drilling is ongoing, with extension drilling targeting the South East
Crescent Zone at depth, while growth drilling targeting the Eastern Breccia is
underway with initial high grade intersections, evidenced by HAD104(6) being
comparable to those seen at the South East Crescent Zone, demonstrating a
promising start
§ Drilling is also underway to continue to assess the broader Havieron
breccia system's suitability for a bulk mining approach
§ Concurrent studies underway to assess production rates greater than 3
million tonnes per annum ("Mtpa")
§ Targeting a further 40,000m of growth drilling in the year to 30 June 2022
which has the potential to further expand the Havieron resource
Shaun Day, Chief Executive Officer of Greatland Gold plc, commented: "This
Mineral Resource and Ore Reserve update represents a considerable increase on
that which was defined in the Stage 1 PFS. The update has unearthed further
aspects of the Havieron system and validates that Havieron is a world class
deposit with significant growth potential. Through an independently verified
analysis, the total Mineral Resource at Havieron has increased to 6.5M oz of
gold equivalent, an increase of almost 50% in 10 months of drilling.
The exceptional 86% rate of conversion of Mineral Resources to Ore Reserves
demonstrates the quality of the high grade South East Crescent Zone at
Havieron.
The South East Crescent Zone Mineral Resource is now defined to around 1,000m
vertical extent below the Permian and still open at depth. In addition, high
grade intercepts are delineated below this level, which further supports the
potential for future Mineral Resource and Ore Reserve growth.
In addition to the Mineral Resources within the Havieron Breccia complex,
growth drilling has now defined an initial Mineral Resource within the
separate Eastern Breccia complex. This is the first Mineral Resource in a
mineralised system outside the Havieron Breccia system and remains open at
depth and to the south. This Eastern Breccia Mineral Resource does not capture
the recent high grade intercepts to its south, which is of similar grade to
the South East Crescent Zone.
With an ongoing and substantial expansion drilling campaign continuing, there
is every opportunity to deliver more growth to the Mineral Resource and Ore
Reserve as we continue to better understand the extent of mineralisation
across the broader Havieron zonation.
The investment proposition for Greatland remains compelling, with this further
understanding of the quality and scale of Havieron supported by this new
Mineral Resource update. With Havieron in a Tier One mining jurisdiction,
under development with a major partner in Newcrest, located near existing
infrastructure and a study indicating modest capex and low operating cost,
this confluence of factors position Havieron as a tremendous and globally
unique asset."
Company's updated Mineral Resource and Ore Reserve estimate
Mineral Resource and Ore Reserve estimates are expressions of judgement based
on knowledge, experience and industry practice. They are also based on a
number of material assumptions (such as future commodity prices and foreign
exchange, cut off grades, future capital and operating costs and development
timeline) which may prove to be incorrect. Estimates which were valid when
originally made may alter significantly when new information or techniques
becomes available. In addition, by their very nature, Mineral Resource and
Ore Reserve estimates are imprecise and depend to some extent on
interpretations, which may prove to be inaccurate. Unless and until actually
mined and processed, no assurance can be given that any estimated tonnage,
grades and recovery levels will be realised or that any Ore Reserves will be
mined or processed economically.
This announcement and the updated Mineral Resource and updated Ore Reserve
estimates for the Havieron Project contained in it have been prepared solely
by Greatland based on relevant available information and has not been reviewed
by Newcrest Mining Limited ("Newcrest"). A subsidiary of Newcrest is the
manager of the Havieron Joint Venture and holds the majority participating
interest in that joint venture (currently 60% with an entitlement (subject to
the terms of the Joint Venture Agreement) to an additional 10% interest and an
option to acquire a further 5% interest at fair market value). Whilst the
information in this announcement pertaining to the estimation and reporting of
Mineral Resources and Ore Reserves has been reviewed and approved by relevant
Competent Persons(4) and the updated Mineral Resource and updated Ore Reserve
estimates have been independently assessed by SRK Consulting (Australasia) Pty
Ltd5, the Company considers that it is possible that: (i) in preparing any
future resource and reserve estimates for the Havieron Project, Newcrest may
adopt different interpretations, assumptions, parameters or plans, or make
different judgements, to those used or made by Greatland in the updated
Mineral Resource and Updated Ore Reserve estimates contained in this
announcement and (ii) the Havieron Joint Venture may choose to carry out its
operations (including the development of the Havieron Project) in a manner
different to the assumptions used in the updated Mineral Resource and updated
Ore Reserve estimates contained in this announcement.
Forward Looking Statements
This document includes forward looking statements and forward looking
information within the meaning of securities laws of applicable jurisdictions.
Forward looking statements can generally be identified by the use of words
such as "may", "will", "expect", "intend", "plan", "estimate", "anticipate",
"believe", "continue", "objectives", "targets", "outlook" and "guidance", or
other similar words and may include, without limitation, statements regarding
estimated reserves and resources, certain plans, strategies, aspirations and
objectives of management, anticipated production, study or construction dates,
expected costs, cash flow or production outputs and anticipated productive
lives of projects and mines.
These forward looking statements involve known and unknown risks,
uncertainties and other factors that may cause actual results, performance and
achievements or industry results to differ materially from any future results,
performance or achievements, or industry results, expressed or implied by
these forward-looking statements. Relevant factors may include, but are not
limited to, changes in commodity prices, foreign exchange fluctuations and
general economic conditions, increased costs and demand for production inputs,
the speculative nature of exploration and project development, including the
risks of obtaining necessary licences and permits and diminishing quantities
or grades of reserves, political and social risks, changes to the regulatory
framework within which Greatland operates or may in the future operate,
environmental conditions including extreme weather conditions, recruitment and
retention of personnel, industrial relations issues and litigation.
Forward looking statements are based on assumptions as to the financial,
market, regulatory and other relevant environments that will exist and affect
Greatland's business and operations in the future. Greatland does not give any
assurance that the assumptions will prove to be correct. There may be other
factors that could cause actual results or events not to be as anticipated,
and many events are beyond the reasonable control of Greatland. Readers are
cautioned not to place undue reliance on forward looking statements,
particularly in the current economic climate with the significant volatility,
uncertainty and disruption caused by the COVID-19 pandemic. Forward looking
statements in this document speak only at the date of issue. Greatland does
not undertake any obligation to update or revise any of the forward looking
statements or to advise of any change in assumptions on which any such
statement is based.
(1 )The gold equivalent (AuEq) is based on assumed prices of US$1,450/oz Au
and US$3.23/lb Cu for Ore Reserve and assumed prices of US$1,600/oz Au and
US$3.50/lb Cu for Mineral Resource and metallurgical recoveries based on block
metal grade, reporting approximately at 88% for Au and 84% for Cu which in
both cases equates to a formula of approximately AuEq = Au (g/t) + 1.5 * Cu
(%). It is the company's opinion that all the elements included in the metal
equivalents calculation have a reasonable potential to be recovered and sold.
(2 )The Net Smelter Return ("NSR") is calculated using metals prices of
US$1,600/oz Au and US$3.50/lb Cu, metallurgical recoveries based on block
metal grade reporting approximately at 88% for Au and 84% for Cu, an USD:AUD
exchange rate of 0.73, as well as treatment and refining costs, payables and
royalties, similar to those in the Stage 1 PFS.
( )
(3 )The Mineral Resource Conversion rate is based on the conversion of
contained metal within the Indicated Mineral Resource to contained metal
within the Ore Reserves, this calculates to 86%.
(4) See Competent Persons Statement below for details.
(5) See Sections 3 and 4 of Appendix 1 below for details.
(6) Refer to announcement "Havieron Exploration Update" dated the 28 January
2022.
Enquiries:
Greatland Gold PLC +44 (0)20 3709 4900
Shaun Day info@greatlandgold.com (mailto:info@greatlandgold.com)
www.greatlandgold.com (http://www.greatlandgold.com)
SPARK Advisory Partners Limited (Nominated Adviser) +44 (0)20 3368 3550
Andrew Emmott/James Keeshan
Berenberg (Joint Corporate Broker and Financial Adviser) +44 (0)20 3207 7800
Matthew Armitt/ Varun Talwar/ Detlir Elezi
Canaccord Genuity (Joint Corporate Broker and Financial Adviser) +44 (0)20 7523 8000
James Asensio/Patrick Dolaghan
Hannam & Partners (Joint Corporate Broker and Financial Adviser) +44 (0)20 7907 8500
Andrew Chubb/Matt Hasson/Jay Ashfield
SI Capital Limited (Joint Broker) +44 (0)14 8341 3500
Nick Emerson/Alan Gunn
Luther Pendragon (Media and Investor Relations) +44 (0)20 7618 9100
Harry Chathli/Alexis Gore
Further Information on the Updated Mineral Resource and Updated Ore Reserve at
Havieron
Project Details
The Project containing the Havieron Au-Cu deposit is centred on a deep
magnetic anomaly 45km east of Telfer in the Paterson Province on the
traditional lands of the Martu people. The Project is held in a joint venture
between Greatland and Newcrest Mining Limited ("Newcrest"), where Newcrest
currently holds a 60% joint venture interest and is entitled (subject to the
terms of the Joint Venture Agreement) to an additional 10% interest, giving an
aggregate interest of 70% (Greatland 30%).
Newcrest may also acquire an additional 5% joint venture interest at fair
market value (under the principles of the Joint Venture Agreement) and, if
exercised, Newcrest will be entitled to an overall joint venture interest of
75% (Greatland 25%). As detailed in the announcement of 21 December 2021,
Newcrest has issued a notice to Greatland informing it that Newcrest would
like to begin the process under the joint venture agreement to seek to agree
or, failing agreement, determine the option exercise price. The Joint
Venture commenced drilling during mid-2019 and has completed 272 drill holes
for 226,492m (at 28 January 2022), with up to eight drill rigs in operation on
the Project.
The Martu people and the Western Desert Land Aboriginal Corporation (WDLAC)
are key project stakeholders. The Martu hold exclusive possession native title
rights and interests over more than 130,000 km(2) of land, including to all
points around the Telfer mine and Havieron Project. The Indigenous Land Use
Agreement (ILUA) with WDLAC, centred on the Telfer mine, extends to the
Havieron project.
The Project is located within granted Mining Lease M45/1287 and has received
the necessary regulatory approvals for the construction of a box cut,
exploration decline and associated surface infrastructure, with these works
formally commencing in January 2021. The Stage 1 PFS released 12 October 2021
has outlined the next stage of the Project which comprises a Feasibility Study
into the underground and surface development to establish the initial mining
area at Havieron and ore processing at Telfer.
The Stage 1 PFS assessed mining production methods including Sub Level Open
Stoping ("SLOS") with mining rates of 2 Mtpa to 3 Mtpa and caving options up
to 6 Mtpa. Surface infrastructure studies were focused on the transportation
of ore to the Telfer processing plant with a range of options considered in
early-stage evaluations including conveyor, rail, pipeline and truck haulage,
with the latter adopted for the Ore Reserve estimate used in the Stage 1 PFS.
Processing studies evaluated a modified Telfer process plant to accommodate
the Havieron ore.
The Stage 1 PFS demonstrated the potential to expand the Project and increase
the mining rate to 3 Mtpa or more based on the upgrading of the October 2021
Inferred Mineral Resources and additional potential Mineral Resource growth
from immediately below the South East Crescent Zone.
This release documents an update prepared solely by Greatland to the Resources
and Reserves documented in the Stage 1 PFS and has not been reviewed by
Newcrest. It is the preference of Greatland to update the Project's Mineral
Resource and Ore Reserve estimates in line with Newcrest; however, in the
context of Greatland's current investigation of potential financing options,
and other Project decisions it may be required to make, it was considered
necessary for the Company to undertake its own analysis (the last Havieron
Mineral Resource and Ore Reserve update being released as part of the Stage 1
PFS with a 5 February 2021 cut-off for drilling information).
Updated Mineral Resource Estimate
The updated Mineral Resource estimate for the Havieron Deposit prepared by
Greatland (Table One) ("Updated Mineral Resource") is based on drilling
completed to 2 December 2021, comprising 311 holes for 209,911m, inclusive of
87 holes for 59,270m which are additional to the drilling data used in the
Stage 1 PFS Mineral Resource and Ore Reserve estimates released on 12 October
2021.
Table One: Updated Mineral Resource estimate tabulation for the Havieron
Deposit (100%)#:
Domain Classification Tonnage Grade Metal Content AuEq (1) Metal
Mt Au (g/t) Cu (%) Au (M oz) Cu (kt) AuEq (M oz)
South East Crescent Indicated 26 3.3 0.52 2.8 136 3.4
Inferred 7 3.2 0.33 0.7 22 0.8
Northern Breccia Indicated 9 1.1 0.11 0.3 10 0.4
Inferred 36 1.0 0.1 1.2 37 1.3
Eastern Breccia Indicated 0.0 0.0 0.0 0.0 0.0 0.0
Inferred 14 1.2 0.09 0.5 13 0.6
Total Indicated 35 2.8 0.42 3.1 146 3.8
Inferred 57 1.3 0.13 2.4 72 2.7
Grand Total Indicated + Inferred 92 1.9 0.24 5.5 218 6.5
(#) Results are reported to one (gold) and two (copper) significant figures to
reflect appropriate precision in the estimate, and this may cause some
apparent discrepancies in totals. Results represent 100% of the Mineral
Resource for Havieron. Mineral Resources in the South East Crescent Zone are
reported within a A$80 NSR/t shell while Mineral Resources in the Breccias are
reported within a A$50 NSR/t shell.
The Updated Mineral Resource estimates are reported as Indicated and Inferred
Mineral Resources in accordance with the 2012 edition of the Australasian Code
for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the
JORC Code). The reported Updated Mineral Resources are inclusive of Ore
Reserves. Refer to details in Appendix 1 (JORC Table 1 - Sections 1 to 3) for
more information relating to data collection and resource estimation.
The Updated Mineral Resource represents a significant increase on the Mineral
Resources defined in the Stage 1 PFS (which was prepared at a 'point in time'
using a 5 February 2021 cut-off for drilling information) including:
§ A 75% increase in total (Indicated plus Inferred) tonnes;
§ A 53% increase in total gold content; and
§ A 63% increase in gold ounces in the Indicated category.
Material differences between the Updated Mineral Resource and the previously
announced Stage 1 PFS Mineral Resource are as follows:
§ A further 38,088 metres of infill drilling completed in the approximately
10 months since 5 February 2021 to 2 December 2021 within the South East
Crescent Zone. This drilling validated both geological and grade continuity of
the Stage 1 PFS South East Crescent Zone Mineral Resource, converting some
Inferred Resource to Indicated Resource;
§ Growth drilling (21,182 metres completed since 5 February 2021 to 2
December 2021) which returned further high-grade results with the South East
Crescent Zone now having a vertical extent of over 1,000 metres and extending
to over 200 metres below the earlier Stage 1 PFS Mineral Resource;
§ The Updated Mineral Resource has been calculated using an A$80 NSR/t value
cut-off for the Crescent material, compared with a A$100 NSR/t cut-off used in
the Stage 1 PFS estimation. Due to the high NSR value of the majority of the
South East Crescent Zone material this change is not considered to have
resulted in a material change in the resources;
§ While different commodity prices have been used (US$1,600/oz Au and
US$3.50/lb Cu and a USD:AUD exchange rate of 0.73 for the Updated Resource
estimate compared with US$1,400/oz Au and US$3.40/lb Cu and a USD:AUD exchange
rate of 0.75 used in the Stage 1 PFS), due to the high NSR value of most of
the South East Crescent Zone material this change is not considered to
resulted in a material change in the South East Crescent Zone Resources. The
increase in the Breccia Mineral Resources within the Havieron Breccia are a
result of additional drilling and some effect of the commodity price variation
between the models; and,
§ The Eastern Breccia Resource, which forms part of the Updated Mineral
Resource was not part of the previous Stage 1 PFS Mineral Resource.
Based on drilling to date the Havieron deposit comprises an ovoid shaped body
of variable brecciation, alteration and sulphide mineralisation with
dimensions of approximately 650m x 350m trending in a north-west orientation,
extending to over 1,100m in depth below 420m of Permian cover.
Within this ovoid body a sulphide rich South East Crescent Zone has been
defined, it is 5-40m wide, extending over 700m in length (when unfolded in
plan just below the basement contact) and defined over 1,000m vertically,
tapering to ~600m in length (unfolded) at this depth and still open at depth.
The South East Crescent Zone has continued to be the focus of drilling and has
been progressively infilled to a nominal drill spacing of 50m for the
Indicated Mineral Resources, and 75m spacing for the Inferred Mineral
Resources.
Gold and copper mineralisation at Havieron consists of breccia, vein and
massive sulphide replacement gold and copper mineralisation typical of
intrusion-related styles of mineralisation. Mineralisation is hosted by
metasedimentary rocks (meta-sandstones, meta-siltstones and meta-carbonate)
and intrusive rocks of an undetermined age. The main mineral assemblage
contains well developed pyrrhotite-chalcopyrite and lesser pyrite sulphide
mineral assemblages as breccia and vein infill, and massive sulphide lenses.
The Eastern Breccia complex comprises a second, separate body of
mineralisation located on the northeast margin of the ovoid body developing
around the 4000mRL (850m below the Permian unconformity), but open at depth
and along strike. The Eastern Breccia comprises broad zones of actinolite
cemented breccia hosted in metasediment rocks, with more abundant vein quartz
and less calcite breccia than the main Havieron deposit breccias. The Eastern
Breccia Mineral Resource is drilled to a nominal 75m x 75m spacing. Infill and
extension drilling of the Eastern Breccia is ongoing.
The Indicated Mineral Resource estimate includes material from the South East
Crescent Zone and adjacent Breccias only. The Inferred Mineral Resource
estimate is comprised of some South East Crescent Zone, the adjacent Breccia
Zones, a portion of the Northern Breccia to an RL of 3950m (~850m below the
Permian unconformity) and the Eastern Breccia where drill data provides
sufficient support to define an appropriate level of geological control and
statistical confidence.
Ordinary Kriging of 5m composites of gold and copper was undertaken into 20m
x 20m x 20m blocks and re-blocked into 4m x 4m x 4m blocks where required. The
Mineral Resource model was domained utilising the geological units defining
the South East Crescent Zone, the Cemented Breccia and Crackle Breccia. Hard
boundaries were used between the Crescent Zone and the Breccia Zones and a
transitional boundary of around 20m was used between the Breccia Zones.
Kriging Neighbourhood Analysis was used to define the search neighbourhood for
gold. Gold, copper and bismuth were estimated independently of each other.
Composite copper, gold and bismuth grades were capped prior to estimation.
Within the Havieron Breccia complex the resource estimation is based entirely
on interpolation while the Eastern Breccia complex, which is considered a
separate system, is based on 70% interpolated and 30% extrapolated blocks
(which is defined as the nearest informing composite being more than 30m away
and estimated by data from fewer than 4 drillholes) representing the early
stage of resource definition in this area. The Mineral Resource model was
validated via visual, statistical, and geostatistical methods.
The Indicated and Inferred Mineral Resource estimate has been constrained
using appropriate drill hole data spacing parameters and geological control.
Resource classification is based on average weighted distance and slope of
regression statistics for estimated gold grades. The Indicated Mineral
Resource classification within the South East Crescent Zone is reported
based on the evaluation of nominal thresholds of the average weighted distance
(45m) and slope of regression (>0.6) and with blocks lying within an A$80
NSR/t shell. The Inferred Mineral Resource classification within the South
East Crescent Zone is reported based on the evaluation of nominal thresholds
of the average weighted distance (75m) and slope of regression (>0.3) and
with blocks lying within an A$80 NSR/t shell.
The Indicated Mineral Resource classification within the Breccias is reported
on the evaluation of nominal thresholds of the average weighted distance (30m)
and slope of regression (>0.6) within an A$50 NSR/t value shell with no
internal selectivity, which assumes bulk mining and therefore includes
internal waste. The Inferred Mineral Resource classification within the
Breccias is reported on the evaluation of nominal thresholds of the average
weighted distance (75m) and slope of regression (>0.3) within an A$50 NSR/t
value shell with no internal selectivity, which assumes bulk mining and
therefore includes internal waste.
The NSR uses metals prices of US$1,600/oz Au and US$3.50/lb Cu, metallurgical
recoveries based on block metal grade, reporting approximately at 88% for Au
and 84% for Cu, an USD:AUD exchange rate of 0.73, as well as treatment and
refining costs, payables and royalties, similar to those used in the Stage 1
PFS.
Reasonable prospects for eventual economic extraction have been assessed
through ongoing mining and processing studies which suggest that selective
underground mining would be appropriate for exploitation of the South East
Crescent Zone, while less selective underground mining would be appropriate
for the exploitation of the mineralised Breccia Zones. There are no known
environmental, social, governmental / regulatory or legal barriers to
declaring this Mineral Resource.
Updated Ore Reserve Estimate
The updated Havieron Ore Reserve estimate prepared by Greatland ("Updated Ore
Reserve") is reported as a Probable Ore Reserve in accordance with the 2012
edition of the Australasian Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves (the JORC Code). For more details regarding the Ore
Reserve estimation process, refer to Appendix 1 (JORC Table 1 - Sections 4).
The Updated Ore Reserve contains 25 Mt at 3.0 g/t Au and 0.44% Cu for 2.4M oz
of gold and 109 kt of copper (Table Two).
Table Two: Updated Ore Reserve estimate tabulation for the Havieron Deposit
(100%)(^):
Tonnage Grade Metal Content AuEq (1) Metal
Mt Au (g/t) Cu (%) Au (M oz) Cu (kt) AuEq (M oz)
Proved - - - - - -
Probable 25 3.0 0.44 2.4 109 2.9
Total Ore Reserve 25 3.0 0.44 2.4 109 2.9
(
^ )Data is reported to one (gold) or two (copper) significant figures to
reflect appropriate precision in the estimate and this may cause some apparent
discrepancies in totals. Data represents 100% of the Ore Reserve for Havieron.
Ore Reserves are reported above a cut-off of A$95 NSR/t and reported within
mining shapes based on a sub-level open stoping mining method. All reported
metal was derived from the South East Crescent Zone only.
This is a significant increase to the Ore Reserves contained in the Stage 1
PFS (prepared at a 'point in time' using a 5 February 2021 cut-off for
drilling information), including:
§ A 50% increase in total gold content;
§ A 84% increase in Reserve tonnes; and,
§ A 86% conversion of Au Metal within the South East Crescent Zone Indicated
Resource to Probable Reserve.
Material differences between the Updated Ore Reserve and the previously
announced Stage 1 PFS Ore Reserve are as follows:
§ The increased drilling completed in the period 5 February 2021 to 2
December 2021, both infilling and extending the Indicated Mineral Resources
defined in the South East Crescent Zone and adjacent Breccias;
§ The Updated Ore Reserve has been calculated using a break even cut off
value of approximately A$95/t milled, and a marginal cut off value of
approximately A$80/t milled, compared to a A$130 NSR/t cut-off used in the
Stage 1 PFS Ore Reserve. The reduced cut-off was calculated from first
principles and the reduction is primarily as a result of increased throughput
from 2 Mtpa to 3 Mtpa, the latter being in line with the Stage 1 PFS
Investment Case carried forward into the Feasibility Study as part of the
Forward Works Program; and
§ Metal price changes from U$1,300/oz to U$1,450/oz for gold, U$3.0/lb to
U$3.23/lb for copper and exchange rate from 0.75 to 0.73 USD per AUD. These
changes had a non-material impact on the overall Ore Reserve as the majority
of the South East Crescent Zone material are well above cut-off value at both
price points. Lower grade material is more sensitive to price assumptions
but makes up a non-material portion of the Ore Reserve.
The Updated Ore Reserve is based on a SLOS mining method with paste fill and
truck ore haulage at a 3 Mtpa mining rate. Metallurgical test-work has been
executed on samples taken from the Havieron deposit during the Stage 1 PFS and
in preceding studies. The test-work undertaken is of an adequate level to
ensure an appropriate representation of metallurgical characterisation and the
derivation of corresponding metallurgical recovery factors.
The Havieron site does not currently have infrastructure to support mining
operations. Major infrastructure requirements are included in the Stage 1 PFS
capital cost estimates, which are based on multiple market prices across all
technical disciplines. Provision has been made for capital expenditure
requirements for new equipment, infrastructure and replacement of
infrastructure and equipment during the life of the mine is based on the Stage
1 PFS. A contingency has been factored into the capital cost estimate
consistent with the level of accuracy of the Stage 1 PFS.
The Updated Ore Reserve is based on the Stage 1 PFS cost estimates. The
Stage 1 PFS cost estimates have been built up from a combination of existing
Telfer site costs scaled for the Havieron material throughput rate, first
principles cost modelling and quotations where practicable.
The Probable Ore Reserve is based on Indicated Mineral Resources and diluting
material only. Metal for Inferred Mineral Resource material was not
considered for the Updated Ore Reserve and did not contribute to the mine
design or economic evaluation. No Measured Mineral Resources are stated for
this deposit and therefore no Proved Ore Reserves were estimated.
The Updated Ore Reserve has been prepared in line with the following bases
used in the Stage 1 PFS:
§ decline, accesses to the levels, ore passes, ventilation raises and other
underground excavations;
§ Sub-level open stoping (SLOS) stopes with paste fill;
§ paste fill plant and underground distribution system;
§ ventilation shafts, fans, regulators and refrigeration equipment;
§ dewatering, electrical and other service equipment; and
§ truck haulage of ore to surface via the access decline.
The following Modifying Factors have been applied to all production shapes to
accurately represent the expected mined tonnes and grades:
§ dilution factors for unplanned overbreak in primary, secondary and tertiary
stopes (average 9%) consisting of waste (average 6%) and stope paste (average
3%);
§ dilution included at zero grade; and
§ mining recovery factor of 97.5%.
The Updated Ore Reserve includes approximately 2.4 Mt of Inferred Mineral
Resource as dilution. The metal contained in this material was not considered
and did not contribute to the economic assessment or metal reported in the
Updated Ore Reserve.
Havieron ore is anticipated to be processed on a campaign basis through the
existing Telfer Train 2 Treatment Plant circuit (consistent with the Stage 1
PFS) and at a throughput of approximately 3 Mtpa. Metal recovery is
expected to be through conventional flotation to produce a copper/gold
concentrate and gold doré through a newly installed flotation tails
carbon-in-leach (CIL) circuit. The technology associated with the ore
processing is conventional and the flowsheet is similar to that utilised by
other operations.
Metallurgical recovery assumptions are based on detailed analysis and
laboratory flotation and leach test work completed on 38 variability samples
during the Havieron Concept Study (2020) and Stage 1 PFS (2021) with good
spatial coverage of the South East Crescent Zone. Of the 38 samples, 8 samples
are located in the Breccia Zones and 30 samples are located in the South East
Crescent Zone, of which 21 samples are located within the Stage 1 PFS South
East Crescent Zone Indicated Mineral Resources. Based on these samples
metallurgical recoveries for gold are anticipated to average approximately 88%
and recoveries of copper are expected to average approximately 84% throughout
the life of the project.
Bismuth is the key deleterious element for the gold/copper concentrate product
with potential smelter penalties incurred on the basis of bismuth content
above a threshold level. The impact of bismuth in concentrate is anticipated
to be managed by mine sequencing and concentrate blending.
The Updated Ore Reserve employs a value-based cut-off determined from the NSR
value equal to the site operating cost included within the Stage 1 PFS. The
NSR calculation takes into account revenue factors, metallurgical recovery
assumptions, transport costs, refining charges, and royalty charges.
The NSR uses metals prices of US$1,450/oz Au and US$3.23/lb Cu, metallurgical
recoveries based on block metal grade, reporting approximately at 88% for Au
and 84% for Cu, an USD:AUD exchange rate of 0.73, as well as treatment and
refining costs, payables and royalties, similar to those used in the Stage 1
PFS.
Detailed environmental studies have been undertaken in the Havieron project
area and include flora and vegetation, fauna, subterranean fauna, waste rock
characterisation, soil and landform study, surface hydrology assessment, a
basic hydrogeological assessment and a greenhouse gas emissions study.
The Havieron project has been designed to recognise biodiversity values and,
through consultation with Martu and their native title corporation (WDLAC),
minimise the impacts to sites and landscapes of cultural significance. The
footprint for the Project has been minimised through the use of existing
tracks and areas of disturbance, as well as utilising the existing Telfer Gold
Mine infrastructure to process the ore and dispose of the tailings material.
Waste rock characterisation has been undertaken and shows that it contains
material which has potentially acid forming (PAF) and metalliferous drainage,
in addition to dispersive or saline material. The portion of PAF material is
less than 1% of total waste volumes. Waste dumps have been designed for the
life of mine that have incorporated cells to safely encapsulate the PAF
material. The waste dump is to be located near the boxcut to minimise haulage
distance and considering the local surface terrain and environmental and
cultural aspects.
The site operating costs include mining cost, processing cost, relevant site
general and administration costs and relevant sustaining capital costs. These
costs equate to a break even cut off value of approximately A$95/t milled, and
a marginal cut off value of approximately A$80/t milled.
Estimation of the Updated Ore Reserve involved standard steps of mine
optimisation, mine design, production scheduling and financial modelling.
Factors and assumptions have been based on benchmarked performance from
similar SLOS operations. The Updated Ore Reserve has been evaluated through a
financial model. All operating and capital costs as well as Ore Reserve
revenue factors stated in this document were included in the financial model.
A discount factor of 4.5% real was applied. This process demonstrated that the
Updated Ore Reserve has a positive NPV. Sensitivities were conducted on the
key input parameters including commodity prices, capital and operating costs,
ore grade, mined tonnes, exchange rate and metallurgical recoveries confirming
the estimate to be robust.
Newcrest stated on 17 February 2022 as part of their Half Year Results Update
that the decline experienced difficulty in poor ground conditions during the
early stages. The team is working to understand the impact on the
development schedule and this may also impact on vertical development. First
production ore is expected in FY24 (rather than H1 FY24) and more updates will
be provided as information comes to hand.
Approvals
A mining lease has been granted over the orebody and a miscellaneous licence
granted along the existing service corridor.
A staged approach for approvals is being undertaken with Stage 1 currently
approved which has allowed the development of the box cut, decline and service
corridor. These approvals also allow for a waste rock dump, evaporation ponds
and supporting infrastructure such as offices and workshops.
Stage 2 approvals are expected to consist of a SLOS underground mine,
permanent infrastructure corridor, associated infrastructure and changes to
Telfer approvals to accept Havieron tailings in existing tailings storage
facilities. The approvals for Stage 2 consist of both Commonwealth and State
level approvals with engagement well advanced with all regulatory bodies. The
approval timelines outlined in the Stage 1 PFS are considered achievable.
For Stage 2 approvals an application is expected to be made for an additional
miscellaneous licence to secure access for an infrastructure corridor to
connect Telfer and Havieron (including haul road, powerlines and water pipes).
This is not considered a risk to the timelines or project.
Indicative Production Profile (100% terms)
The Updated Ore Reserve is based on the updated Indicated Mineral Resource
estimate and approximately 3 Mtpa underground SLOS operation with an expected
mine life of 10 years. Ore is proposed to be transported in trucks along a
new 55km long haul road to the modified processing plant at the Telfer mine
and tailings deposited at Telfer's existing tailings storage facility (TSF).
Multiple stope priority runs were conducted to determine the optimal sequence
which maximised the number of years at peak production while reducing and
compressing the production tail as much as practical. The production rate of
3 Mtpa for the Havieron SLOS was determined by maximising the steady state
production of the sequence.
Table Three: Indicative Updated Ore Reserve Production Profile*:
Year Plant Feed Average Gold Grade Average Copper Grade
(Mt) (g/t Au contained) (% Cu contained)
FY24 0.70 3.26 0.69
FY25 2.16 3.03 0.67
FY26 2.69 3.10 0.47
FY27 2.83 2.78 0.46
FY28 2.90 2.52 0.39
FY29 2.74 2.78 0.37
FY30 2.74 3.21 0.37
FY31 3.03 3.28 0.42
FY32 2.92 3.17 0.35
FY33 1.76 2.82 0.37
FY34 0.47 3.25 0.49
Total 24.92 2.98 0.44
(*)Data is rounded to two decimal places, which may cause some apparent
discrepancies in totals. Data represents 100% of the Ore Reserve for Havieron.
Mine Development and Sequence
Sub-Level Open Stoping (SLOS) is a large-scale open stoping method that is
conducted over multiple levels at once. Once the stope has been mined out it
is backfilled with paste to maintain the overall stability of the opening and
enable mining of adjacent stopes. This method is typically applied to strong
orebodies that require minimal support and are surrounded by competent country
rock, such as the Havieron deposit. Stopes are mined in a checkerboard fashion
with primary stopes mined first, followed by the intermediate secondary
stopes. The mining sequence is globally top down, divided into a number of
different vertical fronts, separated by temporary horizontal sill levels which
are recovered after the levels immediately above and below have been mined and
filled.
A sub-level spacing of 50m with temporary sill levels located 20m below a
mining front were selected. Some sub-level spacings are increased by up to 10m
to accommodate the inclusion of ore, minimising additional level development.
The design consists of ten semi-independent mining sequences, based on both
horizontal and vertical mining fronts.
Infrastructure
The Infrastructure requirements are based on the Stage 1 PFS and contemplate
the transport of ore from the mine to Telfer via road trains on an all-weather
unsealed road. The road has been designed to withstand a 1-in-a-100-year flood
event and maintain access to Havieron.
Power is expected to be supplied to Havieron from Telfer's existing gas power
station via a 66 kilovolt (kV) overhead line running parallel to the nominated
haul road corridor. Further opportunities to replace these with non-fossil
fuel power generation are expected to be evaluated as part of the Feasibility
Study during the Forward Works Program.
Telfer currently operates two processing trains with a total capacity of
~22 Mtpa. The Havieron ore is expected to be processed through a modified
Telfer Train 2 Processing Plant which is expected to operate a single train at
6Mtpa rate on a campaign basis. The Plant modifications are expected to
include magnetic separation within the flotation circuit to reduce the amount
of pyrrhotite in the final Cu Concentrate and a carbon-in-leach (CIL) circuit
on the flotation tail and cyanide detoxification circuit. The expected cost of
the plant modifications is included in the project capital estimate. A single
train operation provides optionality if higher mining rates are achieved from
Havieron or through the extension of Telfer's current mine life (i.e. Telfer
ore can be run through the other train with the existing flowsheet). Tailings
from ore processed is anticipated to be deposited at the existing Telfer TSF.
Independent Review of the Mineral Resource and Ore Reserve Update
SRK Consulting (Australasia) Pty Ltd has completed an independent technical
assessment of the Updated Mineral Resource and Updated Ore Reserve estimates
completed by Greatland for the Havieron deposit. As part of that assessment
SRK reviewed the Resource and Reserve modelling methods and parameters and
found them to be reasonable and to take into consideration all of the current
exploration data and levels of technical knowledge of the Havieron deposit.
SRK considers that the Mineral Resources and Ore Reserves have been reported
in accordance with guidelines and principles outlined in the 2012 edition of
the Australasian Code for the Reporting of Exploration Results, Mineral
Resources and Ore Reserves (the JORC Code, 2012 edition).
Potential Growth with Ongoing Exploration
The Havieron mineral system as outlined by drill testing to date is a 650m by
350m ovate shaped north west trending alteration zone in which mineralisation
is hosted by variable brecciation and sulphide accumulations centred on a
complex of nested diorite intrusions. Higher grade zones are associated with
increases in sulphide accumulations including pyrrhotite, chalcopyrite and
pyrite with quartz. The South East Crescent Zone is a geological domain
characterised by massive sulphide accumulations. Mineralisation has been
observed to over 1,000m in vertical extent below the 420m of post
mineralisation cover sequence.
The Havieron project has significant additional growth potential including:
§ Upgrading of existing Inferred Mineral Resources in both the South East
Crescent Zone and adjacent Breccias;
§ Extension of the South East Crescent Zone below the Updated Mineral
Resource, where increasing grade and thickness of mineralisation has been
observed in recent drilling;
§ Expansion and infill drilling in the Eastern Breccia; and
§ Potential to discover addition mineralisation centres outside of the
immediate ovoid pipe
At the South East Crescent Zone, growth drilling has reported significant
intersections 200m below the Updated Mineral Resource. Drilling continues to
assess the depth extents of South East Crescent Zone which now has a vertical
extent of over 1,000m.
The deepest drill hole within the resource is HAD133W1, approximately 850m
below the unconformity, with the system open beneath this hole.
§ HAD133W1
§ 133m @ 7.0g/t Au & 0.05% Cu from 1,446m
§ including 55.9m @ 9.7g/t Au & 0.04% Cu from 1,449.5m
§ including 20m @ 11g/t Au & 0.04% Cu from 1,519m
The true width of this intersection is approximately 60m.
Results external to or below the Mineral Resource include HAD86W3 and HAD029:
§ HAD086W3
§ 44.7m @ 7.1g/t Au & 0.17% Cu from 1,412m
§ including 20.2m @ 15g/t Au & 0.29% Cu from 1,421m
§ 48m @ 2.2g/t Au & 0.15% Cu from 1,525m
§ including 26.9m @ 3.7g/t Au & 0.26% Cu from 1,538.1m
§ HAD029
§ 134.2m @ 0.81g/t Au & 0.23% Cu from 1,460m
§ including 23m @ 2.7g/t Au & 0.14% Cu from 1,473m
As announced by Greatland on 28 January 2022, HAD086W3 returned two Crescent
Sulphide Zone intersections, with assays for the lower portion of the drill
hole reporting 48m @ 2.2g/t Au & 0.15% Cu from 1,525m, including 26.9m @
3.7g/t Au & 0.26% Cu from 1,538.1m. These results along with high grade
hole HAD133W1, approximately 100m to the southeast continue to support
extensions of the South East Crescent Zone at depth. Drilling continues to
assess the depth extents of the South East Crescent Zone which now has a
vertical extent of over 1000m.
At the Eastern Breccia, drilling targeting strike extensions from previously
reported drill holes HAD083 and HAD084 indicate the potential for the Eastern
Breccia to represent a separate North West trending mineralised corridor, with
an alteration footprint of approximately 600m in strike, adjacent to the ovoid
Havieron breccia system and associated South East Crescent Zone.
Recently reported sulphide rich, Crescent Zone like higher grade zones appear
to be developed internal to this Eastern Breccia Complex. The most significant
intercept to date was returned from HAD104, reporting 62.5m @ 5.9g/t Au &
0.30% Cu from 1,546.5m, including 49.4m @ 7.1g/t Au & 0.38% Cu from
1,554.6m. The intercept is related to massive sulphide and quartz infill,
which is characteristic of the South East Crescent Zone. The intercept is
~200m south east of the previously reported Eastern Breccia drillholes. HAD104
has highlighted the potential for this separate NW trending Eastern Breccia
corridor to host Crescent Sulphide Zone style high grade mineralisation.
Drilling is now focussed on defining the extents of this higher grade
mineralisation seen in HAD104 which remains open in all directions.
Results For HAD104 include:
§ HAD104
§ 62.5m @ 5.9g/t Au & 0.30% Cu from 1,546.5m
§ including 49.4m @ 7.1g/t Au & 0.38% Cu from 1,554.6m
In addition to this release, a PDF version of this report with supplementary
information can be found at the Company's
website: www.greatlandgold.com/media/jorc/
(https://greatlandgold.com/media/jorc/) .
Competent Persons Statements:
Information in this announcement that relates to exploration or development
results has been extracted from the following announcements:
"Havieron Exploration and Development Update", dated 28 January 2022
(Greatland)
"Quarterly Exploration Report", dated 28 January 2022 (Newcrest)
"Havieron Exploration and Development Update", dated 9 December 2021
(Greatland)
"Exploration Update", dated 9 December 2021 (Newcrest)
"Havieron Exploration and Development Update", dated 28 October 2021
(Greatland)
"Quarterly Exploration Report", dated 28 October 2021 (Newcrest)
"Havieron Maiden Pre Feasibility Study", dated 12 October 2021 (Greatland)
"Havieron PFS Stage 1 delivers solid returns and base for future growth" dated
12 October 2021 (Newcrest)
"Havieron Development and Exploration Update" dated 9 September 2021
(Greatland)
"Exploration Update", dated 9 September 2021 (Newcrest)
"Havieron Development and Exploration Update" dated 22 July 2021 (Greatland)
"Quarterly Exploration Report", dated 22 July 2021 (Newcrest)
"Further Excellent Growth Drilling Results at Havieron", dated 10 June 2021
(Greatland)
"Exploration Update", dated 10 June 2021 (Newcrest)
"Excellent Growth Drilling Results at Havieron", dated 29 April 2021
(Greatland)
"Quarterly Exploration Report", dated 29 April 2021 (Newcrest)
"Further Outstanding Infill Drilling Results at Havieron", dated 11 March 2021
(Greatland)
"Exploration Update", dated 11 March 2021 (Newcrest)
"Newcrest Reports Further Drilling Results at Havieron", dated 28 January 2021
(Greatland)
"Quarterly Exploration Report", dated 28 January 2021 (Newcrest)
"Newcrest Reports Further Drilling Results at Havieron", dated 10 December
2020 (Greatland)
"Exploration Update", dated 10 December 2020 (Newcrest)
"Initial Inferred Mineral Resource Estimate for Havieron", dated 10 December
2020 (Greatland)
"Initial Inferred Mineral Resource Estimate for Havieron", dated 10 December
2020 (Newcrest)
"Drilling Results at Havieron Highlight Potential New Eastern Breccia Target",
dated 29 October 2020 (Greatland)
"Quarterly Exploration Report", dated 29 October 2020 (Newcrest)
"Latest Drilling Results at Havieron Highlight Potential Bulk Tonnage Target",
dated 10 September 2020 (Greatland)
"Exploration Update", dated 10 September 2020 (Newcrest)
"Newcrest Identifies New Zone of Breccia Mineralisation at Havieron", dated 23
July 2020 (Greatland)
"Quarterly Exploration Report", dated 23 July 2020 (Newcrest)
"Further Outstanding Drill Results from Havieron", dated 11 June 2020
(Greatland)
"Exploration Update", dated 11 June 2020 (Newcrest)
"Newcrest Reports Further Outstanding Drill Results at Havieron", dated 30
April 2020 (Greatland)
"Quarterly Exploration Report", dated 30 April 2020 (Newcrest)
"Newcrest Reports Further Outstanding Drill Results at Havieron", dated 11
March 2020 (Greatland)
"Exploration and Guidance Update", dated 11 March 2020 (Newcrest)
"Further Outstanding Drill Results at Havieron", dated 30 January 2020
(Greatland)
"Quarterly Exploration Report", dated 30 January 2020 (Newcrest)
"New Outstanding Drill Results at Havieron Extend the Strike Length of
High-Grade Mineralisation",
dated 2 December 2019 (Greatland)
"Exploration Update - Havieron", dated 2 December 2019 (Newcrest)
"Further High-Grade Drilling Results from Newcrest's Campaign at Havieron",
dated 24 October 2019 (Greatland)
"Quarterly Exploration Report - September 2019", dated 24 October 2019
(Newcrest)
"Update on Newcrest Drilling Results at Havieron", dated 10 September 2019
(Greatland)
"Exploration Update - Havieron", dated 10 September 2019 (Newcrest)
"First Results from Newcrest's Drilling Campaign at Havieron", dated 25 July
2019 (Greatland)
"Newcrest Quarterly Exploration Report - June 2019", dated 25 July 2019
(Newcrest)
Information in this announcement pertaining to Reporting of Exploration
Results, including Sampling Techniques and Data, has been reviewed and
approved by Mr John McIntyre, a Member of the Australian Institute of
Geoscientists (MAIG), who has more than 30 years relevant industry
experience. Mr McIntyre is an employee of the Company and has a shareholding
in Greatland Gold plc. Mr McIntyre has sufficient experience relevant to the
style of mineralisation and type of deposit under consideration, and to the
activity which he is undertaking to qualify as a Competent Person as defined
by the 2012 Edition of the Australasian Code for Reporting of Exploration
Results, Mineral Resources and Ore Reserves (the JORC Code) and under the AIM
Rules - Note for Mining and Oil & Gas Companies, which outline standards
of disclosure for mineral projects. Mr McIntyre consents to the inclusion in
this announcement of the matters based on this information in the form and
context in which it appears. Mr McIntyre confirms that the Company is not
aware of any new information or data that materially affects the information
included in the relevant market announcements, and that the form and context
in which the information has been presented has not been materially modified.
Information in this announcement pertaining to Estimation and Reporting of
Mineral Resources, has been reviewed and approved by Mr Stuart Masters, a
Member of the Australian Institute of Geoscientists (MAIG) and a Fellow of
The Australasian Institute of Mining and Metallurgy (FAusIMM), who has more
than 35 years relevant industry experience. Mr Masters is the Principal
Consultant and Director of CS-2 Pty Ltd, and has no financial interest in
Greatland Gold plc or its related entities. Mr Masters has sufficient
experience relevant to the style of mineralisation and type of deposit under
consideration, and to the activity which he is undertaking to qualify as a
Competent Person as defined by the 2012 Edition of the Australasian Code for
Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC
Code) and under the AIM Rules - Note for Mining and Oil & Gas Companies,
which outline standards of disclosure for mineral projects. Mr
Masters consents to the inclusion in this announcement of the matters based
on this information in the form and context in which it appears. Mr
Masters confirms that the Company is not aware of any new information or data
that materially affects the information included in the relevant market
announcements, and that the form and context in which the information has been
presented has not been materially modified.
Information in this announcement pertaining to Estimation and Reporting of Ore
Reserves, has been reviewed and approved by Mr Otto Richter, a Member of The
Australasian Institute of Mining and Metallurgy (MAusIMM), who has more than
20 years relevant industry experience. Mr Richter is an employee of the
Company and has no financial interest in Greatland Gold plc or its related
entities. Mr Richter has sufficient experience relevant to the style of
mineralisation and type of deposit under consideration, and to the activity
which he is undertaking to qualify as a Competent Person as defined by the
2012 Edition of the Australasian Code for Reporting of Exploration Results,
Mineral Resources and Ore Reserves (the JORC Code) and under the AIM Rules -
Note for Mining and Oil & Gas Companies, which outline standards of
disclosure for mineral projects. Mr Richter consents to the inclusion in
this announcement of the matters based on this information in the form and
context in which it appears. Mr Richter confirms that the Company is not
aware of any new information or data that materially affects the information
included in the relevant market announcements, and that the form and context
in which the information has been presented has not been materially modified.
Notes for Editors:
Greatland Gold plc (AIM:GGP) is a leading mining development and exploration
company with a focus on precious and base metals. The Company's flagship asset
is the world-class Havieron gold-copper deposit in the Paterson region of
Western Australia, discovered by Greatland and presently under development in
Joint Venture with Newcrest Mining Ltd.
Havieron is located approximately 45km east of Newcrest's Telfer gold mine
and, subject to a positive decision to mine, will leverage the existing
infrastructure and processing plant to significantly reduce the project's
capital expenditure and carbon impact for a low cost pathway to development.
An extensive growth drilling program is presently underway. Construction of
the box cut and decline to develop the Havieron deposit commenced in February
2021.
Greatland has a proven track record of discovery and exploration success. It
is pursuing the next generation of Tier 1 mineral deposits by applying
advanced exploration techniques in under-explored regions. The Company is
focused on safe, low-risk jurisdictions and is strategically positioned in the
highly prospective Paterson region. Greatland has a total six projects across
Australia with a focus on becoming a multi-commodity mining company of
significant scale.
Appendix 1
JORC Code, 2012 Edition - Table 1
Section 1: Sampling Techniques and Data
Sampling techniques Diamond drilling core samples are obtained from core drilling in Proterozoic
basement lithologies.
Core is cut along the orientation line and one half consistently sampled.
PQ-HQ and NQ diameter core was drilled on a 6m run. Core was cut using an
automated core-cutter and half core sampled at 1m intervals or at breaks for
major geological changes. Sampling intervals range from 0.2 - 2.0m. Sample
weights were typically between 0.6 and 5.9 kg. Cover sequences were not
sampled.
Drilling techniques Permian Paterson Formation cover sequence was drilled using mud rotary
drilling. Depths of cover typically observed to approximately 420m vertically
below surface. Steel casing was emplaced to secure the pre-collar.
Core drilling was advanced from the base of the cover sequence with PQ3, HQ3
and NQ2 diameter double tube coring configuration with minor HQ and PQ triple
tube configuration. Navi drilling was undertaken to start wedged holes from
parent holes.
Core from inclined drill holes are oriented on 3m and 6m runs using an
electronic core orientation tool (Reflex ACTIII). At the end of each run, the
bottom of hole position is marked by the driller, which is later transferred
to the whole drill core run length with a bottom of hole reference line.
Drill sample recovery Core recovery is systematically recorded from the commencement of coring to
end of hole, by reconciling recovered core measurements against driller's
depth blocks in each core tray, as recorded in the database. Driller's depth
blocks provided the depth, interval of core recovered, and interval of core
drilled. Core recoveries below the cover sequence were typically 100%, with
isolated zones of lower recovery. Cover sequence drilling by the mud-rotary
drilling did not yield recoverable samples.
Those sections of wedge holes that were Navi drilled did not produce
recoverable sample material and have not been sampled.
No specific measures have been taken to maximise recovery, other than
employing professional and well respected drillers;
There is no discernible relationship between sample recovery and the grade of
any important variable.
Logging Geological logging recorded qualitative descriptions of lithology, alteration,
mineralisation, veining, and structure (for all core drilled, 209,911 of
drilling from 311 holes drilled up until 2 December 2021, all intersecting
mineralisation), including orientation of key geological features.
Geotechnical measurements including Rock Quality Designation (RQD) fracture
frequency, solid core recovery and qualitative rock strength measurements were
recorded by Geologists or Geotechnical Engineers.
All geological and geotechnical logging was conducted at the Havieron site.
Magnetic susceptibility measurements were recorded every metre. The bulk
density of selected drill core intervals was determined at site on whole core
samples.
Digital data logging was captured on diamond drill core intervals only, and
all data validated and stored in a Datashed database.
All drill cores were photographed (wet and dry), prior to cutting and/or
sampling the core.
The logging is of sufficient quality to support Mineral Resource estimates,
mining studies and metallurgical studies
100 percent of recovered core in the basement rocks has been logged.
Sub-sampling techniques and sample preparation Core was cut and sampled at the Telfer or Havieron core processing facilities.
Half core samples were collected in pre-numbered calico bags and grouped into
bulk bags for dispatch to the laboratory. Sample weights typically varied from
0.7 to 5.6kg. Sample sizes are considered appropriate for the style of
mineralisation. Sample lengths typically ranged from 0.24 to 2m with 54% of
sample being 1m in length. Drill core samples were freighted by air and road
to the laboratory.
Navi drill holes did not produce recoverable material and have not been
sampled.
Sample preparation was conducted at the independent ISO17025 accredited
Intertek Laboratory, Perth (Intertek). Samples were dried at 105(o)C, and
crushed to 95% passing 4.75mm, and then split to obtain up to 3kg sub-sample,
which was pulverised (using LM5) to produce a pulped product with the minimum
standard of 95% passing 106μm. Routine grind size analysis is conducted.
Duplicate samples were collected from crush and pulp samples at a rate of
1:20.
Coarse Crush and Pulp Duplicate results show an acceptable level of
variability for the material sampled and style of mineralisation.
Periodic size checks (1:20) for crush and pulp samples and sample weights are
provided by the laboratory and recorded in the Datashed database. Field
Duplicate samples are not (routinely) taken.
Sampling and sample preparation sizes and quality control protocols are
considered appropriate to the grain size of the material being sampled.
Quality of assay data and laboratory tests Assaying of drill core samples was conducted at Intertek. All samples were
assayed for 48 elements using a 4-acid digestion followed by ICP-AES/ICP-MS
determination (method 4A/MS907), which is considered to provide a total assay
for copper. Gold analyses were determined by 50g fire assay with AAS finish
(method FA50N/AA), which is considered to provide a total assay for gold.
No other analytical methods or tools have been used in the estimation.
Sampling and assaying quality control procedures consisted of inclusion of
certified reference material (CRMs), coarse residue and pulp duplicates with
each batch (at least 1:20). Assays of quality control samples were compared
with reference samples in the Datashed database and verified as acceptable
prior to use of data from analysed batches. Batches failing QA/QC tests were
re-submitted for assay.
Laboratory quality control data, including laboratory standards, blanks,
duplicates, repeats and grind size results are captured in the Datashed
database and assessed for accuracy and precision for recent data.
Extended quality control programs including pulp samples submitted to an
umpire laboratory.
Analysis of the available quality control sample assay results indicates that
an acceptable level of accuracy and precision has been achieved and the
database contains no analytical data that has been numerically manipulated.
The assaying techniques and quality control protocols used are considered
appropriate for the data to be used for reporting Exploration Results and
Mineral Resources.
Verification of sampling and assaying Assessment of reported significant assay intervals was verified by re-logging
of diamond drill core intervals and assessment of high-resolution core
photography. The verification of significant intersections has been completed
by Newcrest personnel and Newcrest's Competent Person/Qualified Person.
No twinned holes have been drilled, however there are many 'wedge/daughter'
holes that provide close-spaced intersections in adjacent holes.
Sampling intervals defined by the geologist are electronically assigned sample
identification numbers prior to core cutting. Corresponding sample numbers
matching pre-labelled calico bags are assigned to each interval.
Electronically generated sample submission forms providing the sample
identification number accompany each submission to the laboratory. Assay
results from the laboratory with corresponding sample identification are
loaded directly into the Datashed database.
No adjustments are made to any assay data.
There are no currently known drilling, sampling, recovery, or other factors
that could materially affect the accuracy or reliability of the data.
Location of data points Drill hole collar locations were surveyed using a differential GPS with GNSS
with a stated accuracy of +/- 0.5m for all drill holes reported.
Drill rig alignment was attained using an electronic azimuth aligner.
Downhole survey was collected at 6-12m intervals in the cover sequence, and
every 6 to 30m in diamond drill core segments of the drill hole using single
shot (Axis Mining Champ Gyro). The single shot surveys have been validated
using continuous survey to surface (Axis Mining Champ) along with a selection
of drill holes re-surveyed by an external survey contactor using a DeviGyro
tool - confirming sufficient accuracy for downhole spatial recording.
All collar coordinates are provided in the Geocentric Datum of Australian
(GDA20 Zone 51). All relative depth information is reported in AHD +5000m.
A LIDAR survey was completed over the project area in Nov 2019 which was used
to prepare a DEM / topographic model for the project with a spatial accuracy
of +/- 0.1m vertical and +/- 0.3m horizontal. The topography is generally low
relief to flat, elevation within the dune corridors in ranges between 250-265m
Australian Height Datum (AHD) steepening to the southeast. Easting and
Northing coordinates are provided in the Geocentric Datum of Australian (GDA20
Zone 51) and all vertical level information is reported in AHD +5000m.
Data spacing and distribution Within the South East Crescent Zone and Breccia Zone and Eastern Breccia drill
hole spacing ranges from 50 by 100m, to 50 by 50m within the current resource
extents. Outside the resource boundary drill hole spacing ranges from 50 to
200m in lateral extent within the Breccia Zone over an area of ~2km2.
The data spacing is sufficient to establish the degree of geological and grade
continuity appropriate for the Mineral Resource and Ore Reserve estimation
procedure(s) and classifications applied.
Samples have not been composited.
Orientation of data in relation to geological structure Drill holes targeting the Crescent Zone are oriented to intersect the steeply
dipping high-grade sulphide mineralisation zones at an angle of greater than
40 degrees. As such, the drilled length of reported intersections is typically
greater than true width of mineralisation in this Zone. Most of these holes
also intersect the adjacent Breccia Zones.
Drill holes targeting the Breccia Zones are oriented to intersect at angles
either broadly perpendicular to the adjacent Crescent Sulphide Zones, or if
drilling away from the South East Crescent Zone area, at intersections broadly
perpendicular to the elongation of the ovoid breccia body. Given the lower
level of understanding of the breccia geometries it is not possible to
quantify the relationship between drilled and true length of reported
intersections in these Zones.
The attitudes of the South East Crescent Zone and Main (Northern) Breccia Zone
and the variety in drilling orientations through such suggest no sample
orientation related biases affect these zones.
The Eastern Breccia, which is interpreted to strike north-westerly and dip
steeply, is intersected almost exclusively with moderate-steep west-to-east
drilling.
Sample security The security of samples is controlled by tracking samples from drill rig to
database.
Drill core was delivered from the drill rig to the Havieron core yard every
shift. On completion of geological and geotechnical logging, core processing
was initially completed by Newcrest personnel at the Telfer facility but later
done at the Havieron facility once it was operational.
Samples were freighted in sealed bags by air and road to the Laboratory,
within the custody of Newcrest representatives. Sample numbers are generated
directly from the database. All samples are collected in pre-numbered calico
bags.
Verification of sample numbers and identification is conducted by the
laboratory on receipt of samples, and sample receipt advice issued to
Newcrest.
Details of all sample movement are recorded in a database table. Dates, Hole
ID sample ranges, and the analytical suite requested are recorded with the
dispatch of samples to analytical services. Any discrepancies logged at the
receipt of samples into the analytical services are validated.
Audits or reviews Internal reviews by Newcrest (JV Manager) of the core handling, sample
preparation and assays laboratories are conducted on a regular basis by both
project personnel and owner representatives and have not identified any
material issues affecting the reliability of the sampling techniques and data.
In the Competent Person's opinion, the sample preparation, security and
analytical procedures are consistent with current industry standards and are
appropriate and acceptable for the styles of mineralisation identified and
will be appropriate for use in the reporting of Exploration Results and
Mineral Resource estimates. No drilling, sampling or recovery factors that
materially impact the reliability of the results of the drilling programme
have been identified.
Section 2: Reporting of Exploration Results
Mineral tenement and land tenure status The Havieron Project is located within mining tenement M45/1287 and is jointly
owned by Greatland Pty Ltd and Newcrest Operations Limited ("Newcrest").
Newcrest has entered into a Joint Venture Agreement (effective 30 November
2020) and Farm-In Agreement (effective 12 March 2019) with Greatland Pty Ltd
and Greatland Gold plc. Newcrest currently holds a 60% joint venture interest
and is entitled (subject to the terms of the Joint Venture Agreement) to an
additional 10% interest, giving an aggregate interest of 70% (Greatland 30%).
Newcrest also has an option to acquire a further 5% joint venture interest at
fair market value.
Newcrest and the WDLAC are parties to an ILUA which relates to the use of
native title land for Newcrest's current operations at Telfer and its
activities within a 60-km radius around Telfer and includes its exploration
activities at Havieron. The parties have agreed that the ILUA will apply to
any future development activities by the Joint Venture Participants (Newcrest
and Greatland) at Havieron.
The mining tenement M45/1287 was granted on 10 September 2020.
Exploration done by other parties Newcrest completed six core holes in the vicinity of the Havieron Project from
1991 to 2003. Greatland Gold completed drill targeting and drilling of nine
Reverse Circulation (RC) drill holes with core tails for a total of
approximately 6,800m in 2018. Results of drilling programs conducted by
Greatland have previously been reported on the Greatland website.
Geology The Havieron Project is located within the north-western exposure of the
Palaeo-Proterozoic to Neoproterozoic Paterson Orogen (formerly Paterson
Province), 45 km east of Telfer. The Yeneena Supergroup hosts the Havieron
prospect and consists of a 9km thick sequence of marine sedimentary rocks and
is entirely overlain by approximately 420m of Phanerozoic sediments of the
Paterson Formation and Quaternary aeolian sediments.
Gold and copper mineralisation at Havieron consist of breccia, vein and
massive sulphide replacement gold and copper mineralisation typical of
intrusion-related and skarn styles of mineralisation. Mineralisation is hosted
by metasedimentary rocks (meta-sandstones, meta-siltstones and meta-carbonate)
and intrusive rocks of an undetermined age. The main mineral assemblage
contains well developed pyrrhotite-chalcopyrite and pyrite sulphide mineral
assemblages as breccia and vein infill, and massive sulphide lenses. The main
mineralisation event is associated with
amphibole-carbonate-biotite-sericite-chlorite wall rock alteration. Drilling
has partially defined the extents of mineralisation which are observed over a
650m by 350m ovoid area, and to depths of up to 1500m below surface.
Drill hole Information Not applicable as this release does not include new Exploration Results.
Refer to previous exploration releases for drillhole information of the
previously reported intercepts highlighted in this report and used in the
Mineral Resource Estimate.
Data aggregation methods Not applicable as this release does not include new Exploration Results.
Refer to previous exploration releases for drillhole information of the
previously reported intercepts highlighted in this report and used in the
Mineral Resource Estimate.
Relationship between mineralisation widths and intercept lengths Not applicable as this release does not include new Exploration Results.
Refer to previous exploration releases for drillhole information of the
previously reported intercepts highlighted in this report and used in the
Mineral Resource Estimate.
Diagrams Diagrams outlining the extent of the Updated Mineral Resources and Updated Ore
Reserves compared to the Stage 1 PFS Resources and Reserves are shown in the
body of the announcement.
Otherwise not applicable as this release does not include new Exploration
Results.
Balanced reporting This report includes highlights of drilling from previously released drillhole
intercepts. There have been twenty one Exploration Results releases for this
project made by Newcrest and Greatland. Previous release dates are 25 July
2019, 10 September 2019, 24 October 2019, 2 December 2019, 30 January 2020, 11
March 2020, 30 April 2020, 11 June 2020, 23 July 2020, 10 September 2020, 29
October 2020, 10 December 2020, 28 January 2021, 11 March 2021, 29 April 2021,
10 June 2021, 22 July 2021, 9 September 2021, 28 October 2021, 9 December 2021
and 28 January 2022.
Previous exploration programs conducted by Newcrest and Greatland have been
reported. Exploration drilling programs are ongoing and further material
results will be reported in subsequent releases.
Other substantive exploration data Not applicable as this release does not include Exploration Results.
Further work Infill and/ or extension drilling is underway on the Inferred Mineral Resource
portion of the South East Crescent Zone, looking to upgrade a significant
portion of the Inferred Mineral Resource to Indicated Mineral Resource;
extension and infill of the Eastern Breccia.
Growth drilling is underway to extend the limits of the mineralised system
down depth and looking to establish additional resources outside those stated
in this announcement.
Section 3: Estimation and Reporting of Mineral Resources
Database integrity Data logged or received by Newcrest are stored in a SQL acQuire database.
Assay and geological data are electronically loaded into acQuire and the
database is replicated in Newcrest's centralised database system
in Melbourne. In-built validation tools are used in the acQuire™ database
and data loggers are used to minimise keystroke errors, flag potential errors
and validate against internal library codes. Regular reviews of data quality
are conducted by site and corporate teams prior to resource estimation.
Final surveyed collars are checked against the original collar GPS pickup and
the Lidar topographic surface. Downhole surveys are checked visually and
statistically for outliers. Assay data is checked for negative, extreme,
missing and overlapping samples. Below detection assay values are set to half
the lower detection limit for estimation. Geological domains are reviewed
against core photography, geochemistry and Corescan data and checked for
overlaps and missing intervals. Data that is found to be in error is
investigated and corrected where possible. If the data cannot be corrected it
is removed from the data set used for resource modelling and estimation.
Newcrest provides Greatland with a 'data pack' approximately every 6 weeks
containing new drilling data and assay results. Assay data is imported into
Greatland's Datashed database directly from the Laboratory assay reports,
including laboratory QA/QC data.
Site visits The Competent Person for Mineral Resources visited Havieron site in November
2021, during which he inspected drilling, sampling, logging, selected drill
core, the core cutting facility which was inactive at the time and is
satisfied that the data and information generated and is suitable for resource
estimation and subsequent reporting in compliance with the JORC Code (2012).
Geological interpretation The geology model defines several mineralised zones, including a Crescent Zone
(containing the sulphide rich material in the area named the "South East
Crescent Zone") and several Breccia types (Cemented Breccia (CB) and Crackle
Breccia (CBX)) and domains (Havieron and Eastern breccias), and several
unmineralised zones (Dolerite Dyke, Calc-silicate country rocks, Permian
sequence and Cover). These zones are based on grouped primary logging domain
codes interpreted from drill cores, mineralogical logs and assay data. GPL has
incorporated much of the previously reported Actinolite Breccia (ACBX) zone
into its CB and CBX zones on the bases of their similarity of spatial grade
distributions and geometries, and absence of sharp contrasts in gold and
copper grades between them. These zones have been modelled into 3D solids in
Leapfrog Geo 6.1 using vein, intrusive and erosional implicant models.
The increased presence of ~northwest trending, steeply dipping diorites in the
breccias corresponds to a increase in grade, but these diorites have not been
modelled. However, their impact is represented to a large extent by the
choice of search neighbourhood parameters.
The confidence in the location and geometry of Crescent Zone is generally high
but decreases as the informing data become more sparse. In some places there
is no distinct grade boundary with the adjacent breccias (especially for gold,
copper and sulphur) and a "buffer" zone was interpreted to represent such, but
analysis of this zone did not support its use in the final model.
The confidence in the location and geometry of the breccias in the Havieron
Breccia zones is variable, but considered moderate in the densely drilled
parts of such. However, the confidence decreases markedly as the scale is
decreased. As such, this model is not a suitable basis for assessing
selective mining options for these zones.
The confidence in the location and geometry of the breccias in the Eastern
Breccia zones is variable, but decreases as the informing data become more
sparse. As such, this model is not a suitable basis for assessing selective
mining options for these zones. In addition, almost all of the drill holes
intersecting these breccias trend from west-to-east.
The confidence in the location and geometry of the Dolerite Dyke, Calc-Shales
and Base of Permian is very high given their relative importance to the
resource estimates.
The interpretation is based mainly on drill hole logging and assay data as
previously described in this Table. In addition, Greatland acknowledges the
extensive ground work undertaken by Newcrest in identifying and interpreting
the geology and agrees with the broad geological domains defined in the
geological model.
The Crescent Zone is generally very well defined and it is difficult to
generate an alternative, plausible and materially different zone from the
available data. The zone is typically intersected where expected by new
drilling.
The Breccia zones are reasonably well defined at a large scale but are much
less well defined at the short scale owing to the low geological and grade
continuity of such. However, it is difficult to generate alternative,
plausible and materially different zones from the available data.
Geological controls on estimation are implicit in the domaining and the nature
of their boundaries. In addition, the ~northwest striking , steeply dipping
trend of the diorites is reflected in the choice of search parameters within
the breccia.
Factors affecting continuity both of grade and geology include the change in
type and intensity of brecciation and breccia fill (veining) across the
Havieron system. Greatland considers the brecciation is logged and modelled in
sufficient detail to be used in the estimation.
Dimension Variable brecciation, alteration and sulphide mineralisation are observed with
a footprint with dimensions of 650m x 350m trending in a north west
orientation and over 1100m in vertical extent below ~420m of cover. The
Crescent Zone Mineral Resource extents are ~550m in unfolded plan section,
between 5-40m true width and 1000m in vertical extent, mineralisation remains
open at depth.
The Breccia Mineral Resource extents occurs as a 50-100m sleeve marginal to
the Crescent Zone Mineral Resource and also a ~250x50x300 NW trending zone in
the north western half on the breccia complex, the "Northern Breccia" which
remains open at depth and to the northwest.
The Eastern Breccia Mineral Resource has dimensions of 200m strike x150m width
x 250m vertical extent.
Estimation and modelling techniques Greatland used nominal 5m composites on a domain-wise basis for variography,
search neighbourhood optimisation and estimation, with the actual composite
length for each intersection adjusted to minimise the amount of 'short tails'.
A geostatistical review using the data up to 2 December 2021 confirmed that
the gold and copper grade distributions showed that the Breccia Zones are
moderately diffusive in nature, and the Crescent Zone is relatively weakly
diffusive in nature. Even though the Crescent Zone is weakly diffusive in
nature, Ordinary Kriging (OK) is considered an appropriate estimator given the
geological setting, geological observations from the logging data, geometry of
the domain and its tenor relative to the likely operating cut-off grade.
That review also broadly confirmed the validity of the variogram models and
search neighbourhoods used by Newcrest for the Stage 1 PFS Model, although
Greatland refined the parameters based on the more extensive data set and an
improved approach to unfolding for the Crescent Zone.
Composite data for gold, copper and bismuth were declustered using a
cell-declustering approach for each domain.
Outlier grades were dealt with through top cutting for each variable on a
domain-basis, with top-cuts generally around the 99th percentile of the
declustered distribution.
Greatland used a 'manual unfolding' method (undertaken in Micromine) for the
Crescent Zone that yielded more robust variograms and subsequently greater
confidence in the variogram models and estimates of gold and copper for this
zone (note that the model blocks were also unfolded, but this meant that
parent-cell estimation could not be used for this zone). This method uses an
underlying controlling surface that represents the mid-surface of the solid
that was created by GPL. Whilst the unfolding was not perfect, it was
considered to be an improvement on the previous approach.
Greatland used a 'trend model' method (undertaken in Micromine) to guide the
estimation of grade and density for the Breccia zones. This approach
generates a locally varying anisotropy (LVA) for each block that orients the
search ellipse and variogram model to the local geometry. This approach does
not explicitly unfold the composite data or block model.
A quantitative kriging neighbourhood analysis (QKNA) was undertaken on gold
for each domain with the aim to maximise the slope-of-regression and kriging
efficiency, whilst minimising the percentage of negative weights. Large
search radii were used but with maximum number of points constraints to meet
these aims. Search ellipsoids were aligned with variogram model ellipses.
All estimates used a hard boundary between the Crescent Zone and other
domains. A transitional boundary of around 20m was used between the Cemented
and Crackle Breccias to reflect the variable nature of this boundary. Only
blocks 10m either side of the Cement and Crackle Breccia boundaries were
allowed to utilise the transitional boundary data, the remainder of the
breccia was estimated from only data within their respective domains.
Density was estimated by OK (rather than IDW previously) on a domain-wise
basis owing to the more extensive database for this model. Whilst density is
most strongly correlated with iron (Fe) and, to a lesser extent, sulphur (S),
it is also significantly influenced by the domain, with the Crescent domain
capturing the high iron and sulphur grades, and thus density, very well.
Gold and copper were estimated in a single pass for each domain, whereas
bismuth and density were estimated using two-passes. Bismuth was primarily
estimated in 2 passes to better honour its spatially bimodal distribution.
Around 30% of the Inferred resources in the Eastern Breccia are based on
composites with a closest distance to the block of more than 30m and data from
less than 4 holes, which GPL has used to define extrapolation.
These blocks are mainly on the edges of the domain as exhibited in the
following plan views at 60m intervals of the extrapolated blocks colour coded
by distance to nearest informing composite (interpolated blocks not shown for
clarity), as well as the location of the informing composites (window +/-10m)
The following table shows the proportion of resource tonnage where the nearest
informing composite is more than 30m away from the block by domain and
category:
Grades and density were estimated in Micromine 2022 software.
The sensitivity of the Crescent Zone gold estimates to various top cut, search
neighbourhood and variogram model parameters was assessed with variations
commensurate with that implied by the resource classification.
There has been no production from Havieron.
Gold and copper are the only revenue generating products assumed to be
recovered. There is sufficient metallurgical testwork to support these
assumptions for the Crescent and Havieron Breccia domains. The Eastern
Breccia domain is assumed to have similar metallurgical properties to the
Havieron Breccia domain. The resource does not include any by-products.
Bismuth has been estimated into the gold-based domains using a similar
approach as for estimating gold and copper, but with bismuth-specific
parameters and a two-pass search plan.
A parent block size of 20x20x20m (East, North, RL) with sub-blocks down to
4x4x4m has been used for all mineralised domains. This is geostatistically
acceptable for the Crescent Zone, where the data density ranges from 50-100m
. Whilst Micromine does not currently support parent-cell estimation for an
unfolded model such as this, the impact of such is deemed negligible. However,
this size is considered small for the Breccia Zones, even though parent-cell
estimation was used for such. Having said this, resources in this domain
have been reported using NSR-based shells that mitigate most of the
detrimental effects of the block size.
The Crescent Zone is almost exclusively estimated to be above the cut-off
grade and minimum stoping thickness (around 4m). Planned stope heights are
well above the block vertical dimension (20m). Change-of-support tests over
various block dimensions also suggest that selectivity issues are unlikely to
be material for this domain. The Breccia Zones are mainly low grade and the
model for such is not designed for assessing selective mining options.
Change-of-support tests revealed significant differences between modelled and
theoretical tonnages and grades at cut-offs well above the reporting cut-off
(A$50 NSR/t).
Domains have principally been defined on gold grade, with copper, iron and
sulphur grades also having a significant impact. Bismuth tends to be well,
albeit variably, correlated with gold and so the gold domains are considered
appropriate for estimating bismuth. Whilst copper is less well correlated to
gold, the gold domains are considered appropriate for estimating copper.
Within these domains gold, copper and bismuth grades have been estimated
independently. Given that each of these elements is assayed for each sample
and the complexities involved in such, the need for co-estimation, such as
co-kriging, was deemed unnecessary.
Other key variables, such as iron, sulphur and cobalt, which Newcrest showed
to be well correlated, were not assessed in great detail or co-estimated as
they are not important for the purposes of this model (i.e., they are not
inputs into metallurgical recovery or NSR formulae).
The geological interpretation controls the resource estimates through the
domaining, boundary controls between domains, and unfolding trend modelling as
previously described.
The grade distributions for gold, copper and bismuth are strongly skewed. In
addition, the very high-grade composites cannot be sub-domained out with the
existing density of data. As such, outlier grades were cut as previously
described.
The estimated block grades and densities were compared to the raw and
composite grades and densities using swath plots, cross-sections and
statistical analysis.
There is no reconciliation data for Havieron.
Moisture All tonnages are calculated and reported on a dry tonnes basis.
Cut-off parameters As Havieron is a multi-element deposit, a Net Smelter Return (NSR) cut-off is
adopted. The generic NSR formula is as follows:
NSR (AUD/t processed) = (Gold Price * Ore Gold Grade * Gold Recovery * Gold
Payability) + (Copper Price * Ore Copper Grade * Copper Recovery * Copper
Payability) - (Treatment, Refining, Freight, Insurance and Selling Costs) -
Penalties - Royalties
The NSR calculation for Mineral Resources takes account revenue factors,
metallurgical recovery assumptions, transport costs, refining charges,
penalties and royalty charges with the gold price of US$1,600 per ounce,
copper price of US$3.50 per pound (US$7,175/t) and an USD:AUD exchange rate of
0.73. Commodity prices and exchange rate forecasts were based on the average
between Long Term 3rd Quartile and Forward Curve price forecasts, as sourced
from Consensus Economics and Bloomberg.
The nominal cut-off value for resource reporting depends on the style and
geometry of mineralisation with the Crescent Zone being amenable to stoping,
whereas the Breccia Zones require a less selective (and lower cost) mining
method. The cut-offs were derived after incorporating mining, haulage,
processing and general and administration costs.
The marginal cut-off for SLOS ("sub-level open stoping" , for the Crescent
Zone) is estimated at A$80 NSR/t, and accounts for mining, haulage, processing
and general and administration costs, which are based on the Stage 1 PFS
Economic Evaluation average Life-of-Mine (LOM) Costs.
The Mineral Resource was defined based on a threshold of A$80 NSR/t within the
Crescent Zone. The vast majority (94%) of the estimated Crescent Zone material
reports above the A$80 NSR/t, as such domaining all material below this
cut-off is not practicable. Areas of Crescent Zone material that had a higher
frequency of blocks below A$80 NSR/t were removed from the classification.
The cut-off for the Breccia Zones (assuming SLC or "sub level caving") is
estimated at A$50 NSR/t, and accounts for mining, haulage, processing and
G&A costs, which are based on the PFS Analysis.
For the Breccia Mineral Resources, a smoothed shell was generated in Leapfrog
Version 2021.1.3 based on a threshold of A$50 NSR/t and includes internal
below value cut-off blocks and excludes isolated above cut-off blocks. As
the Breccia Resources are consider non-selective bulk mining domains all
sub-economic material within the final A$50 NSR/t shell was classified to
represent the non-selective nature.
Both SE Crescent Mineral Resources and Breccia Mineral Resources are
representing the limit of reasonable prospects of eventual economic
extraction. The A$80 NSR/t cut-off for SE Crescent Mineral Resources and
A$50 NSR/t cut-off for Breccia Mineral Resources are based on current
understanding of the Havieron deposit and other benchmarked operations.
Greatland used smoothed NSR shells to define its resources and this results in
some material below the nominal cut-off to be included in the resources. The
following table shows the total and proportion of the Mineral Resource
tonnages and average NSR/t's below the nominal cut-off NSR each
Domain/Lode/category combination.
Mining factors or assumptions The Stage 1 PFS showed that the Crescent Zone and immediately adjacent diluent
material is amenable to mining by sub-level open stoping (SLOS) with minimum
mining dimensions of 5mW x 15mL x 25mH. The updated resource model supports
that finding.
The Stage 1 PFS suggests that the Breccia Zones may be amenable to, and
require the lower costs of, bulk mining methods such as sub-level caving
(SLC). SLC is likely to require minimum mining dimensions of 80mW x 100mL x
100mH. Whilst SLC would likely require a temporary pillar near the top to
act as a buffer between the cave and the Permian cover, this material may be
recoverable as part of the cave draw and so it is not excised from the Mineral
Resources. Furthermore, the Mineral Resources assume there will be no
significant permanent pillars in the resource volume, although it is possible
that a pillar will need to be left between the paste-filled Crescent Zone
stopes and the Breccias, and which will be accounted for during Ore Reserve
estimation.
Metallurgical factors or assumptions It is anticipated that Havieron ore will be processed on a campaign basis
through the Telfer Train 2 Treatment Plant circuit at a throughput of
approximately 3 Mtpa. It is anticipated that metal will be recovered
through conventional flotation to produce a copper/gold concentrate and a gold
doré through a newly installed flotation tails carbon-in-leach (CIL) circuit.
The technology associated with the ore processing is conventional and the
flowsheet is similar to that utilised by other operations.
Metallurgical recovery assumptions are based on detailed analysis and
laboratory flotation and leach test work completed on 38 variability samples
during the Havieron Concept Study (2020) and Stage 1 PFS (2021) with good
spatial coverage of the Crescent Zone Domain. Of the 38 samples, 8 samples are
located in the Havieron Breccia Zones and 30 samples are located in the
Crescent Zone Domain, of which 21 samples are located within the Indicated
Mineral Resources in this domain. Based on these samples, metallurgical
recoveries for gold are anticipated to average approximately 88% and
recoveries of copper are expected to average approximately 84% throughout the
life of the project. Note that GPL does not have any metallurgical testwork
results for the Eastern Breccias and it is assumed that they have similar
metallurgical properties to their corresponding Havieron Breccias.
Environmental factors or assumptions Detailed environmental studies have been undertaken in the Project area and
include flora and vegetation, fauna, subterranean fauna, waste rock
characterisation, soil and landform study, surface hydrology assessment, a
basic hydrogeological assessment and a greenhouse gas emissions study.
The Project has been designed to recognise biodiversity values and, through
consultation with Martu and their native title corporation (WDLAC), minimise
the impacts to sites and landscapes of cultural significance. The footprint
for the Project has been minimised through the use of existing tracks and
areas of disturbance, as well as utilising the existing Telfer Gold Mine
infrastructure to process the ore and dispose of the tailings material.
Waste rock characterisation has been undertaken and shows that it contains
material which has potentially acid forming (PAF) and metalliferous drainage,
in addition to dispersive or saline material. The portion of PAF material is
less than 1% of total waste volumes. Waste dumps have been designed for the
life of mine that have incorporated cells to safely encapsulate the PAF
material. The waste dump is to be located near the boxcut to minimise haulage
distance and considering the local surface terrain and environmental and
cultural aspects.
A staged approach for approvals is being undertaken, with Stage 1 currently
approved, which has allowed the development of the boxcut, decline and service
corridor. These approvals also allow for a waste rock dump, evaporation ponds
and supporting infrastructure such as offices and workshops.
Stage 2 approvals are expected to consist of a SLOS underground mine,
permanent infrastructure corridor, associated infrastructure and changes to
Telfer approvals to accept Havieron tailings in existing tailings storage
facilities.
Bulk Density Havieron has an extensive database of bulk density measurements based on the
Archimedes method (water immersion) of 10-20cm samples taken at 10-50m
intervals down the hole. Whilst the geology, and thus density, can change
rapidly down the hole, the number of measurements means that the data set is
likely to be representative for the purposes of this estimate.
Most of the core in the mineralised zones is very competent and of low to
negligible porosity.
Bulk density is estimated into blocks using OK on a domain-specific basis.
The variability of density is relatively low in the Breccia zones and the
scope for an estimation related bias is very low, even at the local scale.
The variability of density in the Crescent zone is higher and, whilst local
estimation-related biases may occur, it is unlikely that a significant global
bias exists.
Classification Resources preliminarily classified on the basis of the quality and quantity of
data, the geological and grade continuity, and the confidence in the gold
grade estimates. Data quality is implicitly accounted for by excluding
unreliable data from the estimate.
Confidence in the estimate was initially assessed using the
'Slope-of-regression', 'Average Distance to informing composites', 'Closest
Distance to informing composites', 'Kriging Efficiency', 'Number of Informing
Drill Holes', and 'Number of Informing Composites' statistics stored during
estimation. The schema was then simplified to only account for the
'Slope-of-regression' and 'Average Distance to informing composites'
statistics. Shells based on these two statistics were computed at various
thresholds for each of the domains. The chosen nominal parameters were:
Domain Category Slope Average Distance
CRS Indicated >0.6 <45m
CRS Inferred >0.3 <75m
Breccias Indicated >0.6 <30m
Breccias Inferred >0.3 <75m
This approach led to some blocks not meeting these criteria to be included and
some meeting these criteria to be excluded from the shells. Furthermore,
some edges were manually trimmed to ensure continuity of classification.
The final classification then considered the 'reasonable prospects of eventual
economic extraction', and specifically the mineability by the proposed method,
the recoverability by the proposed processing method, and the likelihood that
the resource would be above the cut-off.
Several early drill holes were deemed to be of low reliability and were
excluded from the estimation. All remaining data are considered to be
suitable for the purposes of resource estimation.
Geological and grade continuity in the Crescent Zone can reasonably be assumed
in most places, and implied elsewhere. When combined with the density and
orientation of data, as well as the likelihood and impact of any
misestimation, this supports the assigned Indicated (assumed) and Inferred
(implied) resources classification.
Geological and grade continuity in the Breccia zones are typically much
lower. However, the data density is moderate-high in the southern parts of
the Breccias adjacent to the Crescent Zone and geological and grade continuity
can be reasonably assumed. As such, some of this material has been assigned
as Indicated resources. The remainder of the Breccia Zone has been assigned as
Inferred resources as the continuity of geology and grade can only be implied
from the available data. The confidence in the estimates of the Breccia
zones decreases rapidly as the cut-off is increased and significant
misrepresentation of tonnages, grades and location above elevated cut-offs in
this model is likely, and so the classification is strictly only applicable at
the reporting cut-off A$50 NSR/t.
The classification appropriately reflects the views of the Competent Person.
Audits or reviews SRK Consulting (Australasia) Pty Ltd has completed an independent technical
assessment of the 2022 Mineral Resource estimates completed by Greatland for
the Havieron gold and copper deposit. As part of that assessment, SRK reviewed
the resource modelling methods and parameters and is of the opinion that they
are reasonable and take into consideration all of the current exploration data
and levels of technical knowledge of the Havieron deposit. SRK considers that
the Mineral Resources have been reported in accordance with guidelines and
principles outlined in the 2012 edition of the Australasian Code for the
Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC
Code, 2012 edition).
Discussion of relative accuracy / confidence Greatland has conducted Change-of-Support studies using the Discrete Gaussian
Method for the Crescent Zone and Breccia Zones. These studies revealed that
the estimates for the Crescent Zone are robust within the context of the
likely operating cut-off value. The studies also revealed that the estimates
for the Breccia Zones are reasonable at the likely operating cut-off (A$50
NSR/t), but this accuracy rapidly diminishes as the cut-off is increased.
There is no historical production from Havieron.
This approach led to some blocks not meeting these criteria to be included and
some meeting these criteria to be excluded from the shells. Furthermore,
some edges were manually trimmed to ensure continuity of classification.
The final classification then considered the 'reasonable prospects of eventual
economic extraction', and specifically the mineability by the proposed method,
the recoverability by the proposed processing method, and the likelihood that
the resource would be above the cut-off.
Several early drill holes were deemed to be of low reliability and were
excluded from the estimation. All remaining data are considered to be
suitable for the purposes of resource estimation.
Geological and grade continuity in the Crescent Zone can reasonably be assumed
in most places, and implied elsewhere. When combined with the density and
orientation of data, as well as the likelihood and impact of any
misestimation, this supports the assigned Indicated (assumed) and Inferred
(implied) resources classification.
Geological and grade continuity in the Breccia zones are typically much
lower. However, the data density is moderate-high in the southern parts of
the Breccias adjacent to the Crescent Zone and geological and grade continuity
can be reasonably assumed. As such, some of this material has been assigned
as Indicated resources. The remainder of the Breccia Zone has been assigned as
Inferred resources as the continuity of geology and grade can only be implied
from the available data. The confidence in the estimates of the Breccia
zones decreases rapidly as the cut-off is increased and significant
misrepresentation of tonnages, grades and location above elevated cut-offs in
this model is likely, and so the classification is strictly only applicable at
the reporting cut-off A$50 NSR/t.
The classification appropriately reflects the views of the Competent Person.
Audits or reviews
SRK Consulting (Australasia) Pty Ltd has completed an independent technical
assessment of the 2022 Mineral Resource estimates completed by Greatland for
the Havieron gold and copper deposit. As part of that assessment, SRK reviewed
the resource modelling methods and parameters and is of the opinion that they
are reasonable and take into consideration all of the current exploration data
and levels of technical knowledge of the Havieron deposit. SRK considers that
the Mineral Resources have been reported in accordance with guidelines and
principles outlined in the 2012 edition of the Australasian Code for the
Reporting of Exploration Results, Mineral Resources and Ore Reserves (the JORC
Code, 2012 edition).
Discussion of relative accuracy / confidence
Greatland has conducted Change-of-Support studies using the Discrete Gaussian
Method for the Crescent Zone and Breccia Zones. These studies revealed that
the estimates for the Crescent Zone are robust within the context of the
likely operating cut-off value. The studies also revealed that the estimates
for the Breccia Zones are reasonable at the likely operating cut-off (A$50
NSR/t), but this accuracy rapidly diminishes as the cut-off is increased.
There is no historical production from Havieron.
Section 4: Estimation and Reporting of Ore Reserves
Mineral Resource Estimate for conversion to Ore Reserves Havieron is a gold and copper deposit located within the boundaries of the
East Pilbara Shire in the Paterson Province, Western Australia (WA), and is
located approximately 45 kilometres (km) east of Newcrest's fly-in fly-out
Telfer Mine. The Havieron deposit lies unconformably below approximately 420
metres (m) of post-mineral, flat-lying Permian fluvio-glacial sediments of the
basal sequence rocks in the Palaeozoic Canning Basin.
The geology model represents several mineralised zones, including a Crescent
Zone (containing the sulphide rich material in the area named the South East
Crescent Zone) and several Breccia types (Cemented Breccia (CB) and Crackle
Breccia (CBX)) and domains (Havieron and Eastern breccias), and several
unmineralised zones (Dolerite Dyke, Calc-silicate country rocks, Permian
sequence and Cover). These zones are based on grouped primary logging domain
codes interpreted from drill cores, mineralogical logs and assay data.
The February 2022 Updated Mineral Resource Estimate (Updated Mineral Resource)
was used as the basis for the February 2022 Ore Reserve Update.
Mineralisation of gold and copper in the Updated Mineral Resource are within
the Crescent and the Breccia Zones. High grade gold mineralisation is
associated with a massive sulphide zone termed the Crescent Zone which occurs
on the margin of the Breccia. The Crescent Zone is characterised by a series
of massive to semi-massive sulphide replacement units that have a subvertical
dip and is best developed on the SE of the system forming as arcuate, crescent
like geometry.
The Crescent Zone is 5-40 m wide, extending 700m in length in unfolded section
from the basement contact and defined over 1,000 m vertically, tapering to
~600 m in length and open at that depth. The South East Crescent Zone has
continued to be the focus of drilling and has been progressively infilled to
a nominal drill spacing of 50m for the Indicated Mineral Resources, and 75m
spacing for the Inferred Mineral Resources.
OK estimation has been used for gold, copper, bismuth and density. A panel
size of 20 mE x 20 mN x 20 mRL was used for both the SE Crescent and Breccias
with sub-blocking allowed down to a size of 4 mE x 4 mN x 4 mRL.
The Updated Mineral Resource estimate for the South East Crescent has been
classified as Indicated Mineral Resource and Inferred Mineral Resource based
on data quality and quantity factors as well as geological domaining,
estimation confidence and reasonable prospect of the eventual economic
extraction (RPEEE).
The Updated Mineral Resource is reported inclusive of Ore Reserves.
Site Visits Greatland's Competent Person for the Ore Reserve estimate visited site in
November 2021. A general Havieron site tour was conducted of the camp, boxcut
and decline, exploration drilling, core farm, and of the Telfer camp and
processing plant. Operational challenges were noted with unconsolidated
material in the upper part of the decline and discussions were held with the
operations team and decline contractor regarding trials underway to determine
optimal cut length, development cycle and support measures to ensure the
effective progress of the decline.
Newcrest stated on 17 February 2022 as part of their Half Year Results Update
that the decline experienced difficulty in poor ground conditions during the
early stages. The team is working to understand the impact on the
development schedule and this may also impact on vertical development. First
production ore is expected in FY24 (rather than H1 FY24) and more updates
will be provided as information comes to hand..
The Competent Person has undertaken sufficient investigations of the mine plan
and material Modifying Factors applied to create the mine plan to satisfy
himself that the Ore Reserves have been appropriately estimated and reported
in compliance with the 2012 edition of the JORC Code.
Study Status A Stage 1 PFS was completed to generate the supporting basis for the maiden
Havieron Ore Reserve Estimate published in October 2021. The mine design and
schedule were updated in February 2022 to reflect the resource model changes
presented in the February 2022 Resource Model Update and forms the basis for
this Ore Reserve Update. This update is considered to remain at a
Pre-Feasibility level of confidence and shows that the mine plan remains
technically achievable and economically viable taking into consideration
currently known material Modifying Factors.
Cut-off Parameters The Ore Reserve employs a value-based cut-off determined from a Net Smelter
Return (NSR) to account for the contributions from multi-elements, at a value
equal to the site operating cost. The generic NSR formula is as follows:
NSR (AUD/t processed) = (Gold Price * Ore Gold Grade * Gold Recovery * Gold
Payability) + (Copper Price * Ore Copper Grade * Copper Recovery * Copper
Payability) - (Treatment, Refining, Freight, Insurance and Selling Costs) -
Penalties - Royalties
Metal price assumptions are as listed in the relevant "Revenue Factors"
section. The underlying cost assumptions remained largely the same between the
October 2021 Stage 1 PFS and this February 2022 Update, and is in line with
the 3 Mtpa Investment Case presented in the Stage 1 PFS.
The NSR calculation takes into account revenue factors, metallurgical recovery
assumptions, transport costs, refining charges, and royalty charges.
The site operating costs include mining cost, processing cost, relevant site
general and administration costs and relevant sustaining capital costs. This
cost equates to a break even cut off value of approximately AUD95/t milled,
and a marginal cut off value of approximately AUD80/t milled.
Metallurgical recovery and cost assumptions are discussed in more detail under
the relevant headings in Table 1 - Section 4.
Mining factors or assumptions Estimation of the Ore Reserve Update is based on the February 2022 Resource
Model Update and involved standard steps of mine optimisation, mine design,
production scheduling and financial modelling. The basis of the analysis is an
update to the Stage 1 PFS and is considered to remain at a Pre-Feasibility
Level of confidence.
The Ore Reserve Update supports the appropriateness of the selected mining
method (Sub-Level Open Stoping) at a 3 Mtpa mining rate as the basis of the
Ore Reserve estimate.
Back fill type Cemented paste fill
Materials handling system Decline trucking
Stope dimensions Width Minimum 5m to Maximum 30 m
Length 15 to 20 m
Sublevel height 25 to 60m, average 50m
The following Modifying Factors have been applied to all mining shapes to
accurately represent the expected mined tonnes and grades:
· Dilution factors for overbreak in primary, secondary and tertiary
stopes (average 9%), consisting of waste (average 6%) and stope paste (average
3%); Dilution tonnes were estimated as an equivalent depth of failure based on
geotechnical estimations, applied to the individual stope walls and in the
respective stoping sequence, to estimate paste and waste rock volumes and
expressed here as an average percentage of the overall stope tonnes.
· Dilution included at zero grade; and
· Mining recovery factor of 97.5%, based on the near vertical
nature of the stopes, proposed mining method and geotechnical estimation of
overall stope stability.
The ultimate extent of the deposit remains open and orebody knowledge will
increase as drilling and mining progress. Current mining modifying factors
are based on known data to date and may change as new information becomes
available.
The February 2022 Resource Model is comprised of Indicated Mineral Resources
and Inferred Mineral Resources. Mine plans are based on the definition of
mining shapes only considering the contribution of metal from Indicated
Mineral Resources.
Ore Reserves estimates and statements are required to include estimates of
dilution. The dilution included in the total Ore Reserve is approximately
2.7Mt which is comprised of Inferred and Unclassified Mineral Resources, waste
host rock and paste fill dilution. Metal from the Inferred and Unclassified
Mineral Resource material was not considered in the economic assessment of the
stopes.
The Havieron Project is a greenfield mining project and will require the
following mining infrastructure to support the mine:
· decline, accesses to the levels, ore passes, ventilation raises
and other underground excavations
· paste fill plant and underground distribution system
· ventilation fans, regulators and refrigeration equipment
· dewatering, electrical distribution and other service equipment
Non-mining infrastructure is discussed in more detail under the Infrastructure
section.
Metallurgical factors or assumptions It is anticipated that Havieron underground ore will be processed on a
campaign basis through the existing Telfer Train 2 Treatment Plant circuit at
a throughput of approximately 3 Mtpa, with tailings being disposed in the
current Telfer Tailings Storage Facility. Metal recovery is anticipated to
be through conventional flotation to produce a copper/gold concentrate and
gold doré through a newly installed flotation tails carbon-in-leach (CIL)
circuit. The technology associated with the ore processing is conventional and
the flowsheet is similar to that utilised by other operations.
Metallurgical recovery assumptions are based on detailed analysis and
laboratory flotation and leach test work completed on 38 variability samples
during the Havieron Concept Study (2020) and Stage 1 PFS (2021) with good
spatial coverage of the Crescent Zone. Of the 38 samples, 8 samples are
located in the breccia zones and 30 samples are located in the Crescent Zone,
of which 21 samples are located within the Crescent Zone Indicated Mineral
Resources. Based on these samples, average life of mine metallurgical
recoveries are estimated to be:
· gold: approximately 88%, and
· copper: approximately 84%, variable on block metal grade.
Bismuth is the key deleterious element for the gold/copper concentrate product
with smelter penalties incurred on the basis of bismuth content. It is
anticipated that the impact of bismuth in concentrate will be managed by mine
sequencing and concentrate blending.
Bulk sample or pilot scale test work has not been undertaken.
Environmental Detailed environmental studies have been undertaken in the project area and
include flora and vegetation, fauna, subterranean fauna, waste rock
characterisation, soil and landform study, surface hydrology assessment, a
basic hydrogeological assessment and a greenhouse gas emissions study.
The Project has been designed to recognise biodiversity values and, through
consultation with Martu and their native title corporation (WDLAC), minimise
the impacts to sites and landscapes of cultural significance. The footprint
for the Project has been minimised through the use of existing tracks and
areas of disturbance, as well as utilising the existing Telfer Gold Mine
infrastructure to process the ore and dispose of the tailings material.
Waste rock characterisation has been undertaken and shows that it contains
material which has potentially acid forming (PAF) and metalliferous drainage,
in addition to dispersive or saline material. The portion of PAF material is
less than 1% of total waste volumes. Waste dumps have been designed for the
life of mine that have incorporated cells to safely encapsulate the PAF
material. The waste dump is to be located near the boxcut to minimise haulage
distance and considering the local surface terrain and environmental and
cultural aspects.
A staged approach for approvals is being undertaken, with Stage 1 currently
approved, which has allowed the development of the boxcut, decline and service
corridor. These approvals also allow for a waste rock dump, evaporation ponds
and supporting infrastructure such as offices and workshops.
Stage 2 approvals are expected to consist of a SLOS underground mine,
permanent infrastructure corridor, associated infrastructure and changes to
Telfer approvals to accept Havieron tailings in existing tailings storage
facilities.
Infrastructure Havieron is a greenfield mining project and will require the following
infrastructure to support mining operations:
· Ventilation fans and refrigeration equipment;
· Paste plant;
· Surface Mining Infrastructure Area (MIA) including camp, offices,
workshops, evaporation ponds, electrical substations, explosive magazines,
batch plant, waste dumps, ore stockpile, and other facilities;
· Haulage road and Service Corridor to transport the ore from
Havieron to the Telfer Processing Plant and run overhead powerlines along the
Service Corridor to extend electrical power from the existing Telfer gas fired
power station to Havieron; and
· Modifications to the existing Telfer Processing plant to treat
the ore coming from Havieron.
The capital and operating costs for the above have been estimated in the Stage
1 PFS. The infrastructure estimates for this Ore Reserve Update remains in
line with the Stage 1 PFS, with additional allowance made for ventilation and
processing due to a slightly deeper ultimate depth and in line with the
expanded mine plan.
Access to Telfer Mine is already in place via the Telfer Access Road. Telfer
Mine has an existing camp, sealed runway and airport, gas-fired power station
and processing plant.
Costs Capital and operating costs underlying assumptions are to a PFS level. Capital
cost estimates are based on multiple market prices across all technical
disciplines and include processing upgrade and mine development costs along
with associated surface and underground infrastructure, project establishment
and sustaining capital costs. These provisions have been allowed for during
the life of the mine based on the Stage 1 Study estimates. Contingency has
also been factored into the project capital cost estimate consistent with the
level of accuracy of the study.
Newcrest stated on 17 February 2022 as part of their Half Year Results Update
that the decline experienced difficulty in poor ground conditions during the
early stages. The team is working to understand the impact on the
development schedule and this may also impact on vertical development. First
production ore is expected in FY24 (rather than H1 FY24) and more updates
will be provided as information comes to hand.
The operating cost estimates are in line with the Stage 1 PFS, which were
sources from current Telfer rates and contractor schedule of rates submitted
for PFS budget purposes and are inclusive of:
· mining cost: development by drive type and ground support
profile, longhole drilling and blasting, haulage for ore and waste, labour,
maintenance and other fixed costs
· electrical power cost based on estimated power consumption and
supply from Telfer Power Plant
· surface transport cost to Telfer Processing plant
· processing cost and
· relevant site general and administration costs.
Ore Reserve cost estimates have been independently reviewed and are considered
to be at an appropriate level for a PFS.
The Stage 1 PFS transport and refining charges have been developed from first
principles consistent with the application of the current Telfer operation.
These included charges for deleterious elements, e.g. bismuth where
applicable. These assumptions and estimates were carried forward into the
February 2022 Update.
Costs include a revenue-based payment from mining the Havieron Project area
under the ILUA with WDLAC.
State royalties are 2.5% for gold, 5% for copper after allowable deductions.
Revenue factors Long term metal prices and exchange rate assumptions adopted for estimating
this Ore Reserve Update are US$1,450/oz for gold, US$3.23/lb for copper, at a
USD:AUD exchange rate of 0.73. Commodity prices and exchange rate forecasts
were based on the Median Long Term price forecasts, as sourced from Consensus
Economics and Bloomberg. These price assumption are higher than the
US$1,300/oz for gold and US$3.00/lb for copper and USD:AUD exchange rate of
0.75 assumed for the October 2021 Stage 1 Study, but were selected in line
with median long term consensus price forecasts and historical metal prices
over the past 5 years.
An NSR value calculation was adopted, taking into account Ore Reserve revenue
factors, metallurgical recovery assumptions, transport costs and refining
charges and royalty charges.
Market assessment Gold will be sold on the open market and subject to price fluctuations. Supply
and demand for gold from Telfer and Havieron is not considered a constraint in
the estimation of the Ore Reserve.
Telfer has sold copper concentrate for its operational life into the world
concentrate markets and this is assumed to continue under conditions similar
to Newcrest's current market agreements over the life of the operational plan.
Concentrate volume forecasts were derived from the Updated Ore Reserve
production schedule.
Economic The Ore Reserve has been evaluated through a financial model on a real
cashflow basis. All operating and capital costs as well as revenue factors
stated in this document were included in the financial model. A discount
factor of 4.5%pa real was applied. This process demonstrated the Havieron Ore
Reserve to have a positive NPV at current assumptions.
Sensitivities were conducted on the key input parameters including commodity
prices, capital and operating costs, ore grade, mined tonnes, exchange rate
and metallurgical recoveries confirming the estimate to be robust.
Social The traditional landowners, the Martu people and the WDLAC are key project
stakeholders. The Martu hold exclusive possession native title rights and
interests over more than 130,000km(2) of land, including to all points around
the Telfer mine and Havieron Project. The ILUA with WDLAC, centred on the
Telfer mine, extends to the Havieron Project.
Other The only identified material naturally occurring risk at Havieron is flooding
from large rain events typically associated with the cyclone season. The
existing boxcut has been located and all other surface connections to the
surface have been designed above a modelled 1 in 1,000 year Average Recurrence
Interval (ARI) event where possible, or will be elevated such that large
volumes of water cannot enter the mine workings.
A number of State and Commonwealth statutory requirements are relevant to the
Havieron Project and all aspects of the Project will comply with the relevant
Government Acts and Regulations applicable in the jurisdiction of Western
Australia.
Approvals
A Mining Lease has been granted over the orebody, and miscellaneous licence
granted along the existing service corridor.
A staged approach for approvals is being undertaken with Stage 1 currently
approved which has allowed the development of the boxcut, decline and service
corridor. These approvals also allow for a waste rock dump, evaporation ponds
and supporting infrastructure such as offices and workshops. Minor additional
approvals are in the process of being obtained and include a Groundwater
Licence amendment and Part V approval to allow the operation of the
evaporation ponds, waste water treatment plant and to allow construction of a
landfill for non-mineralised waste.
The Part V licence and registrations have approved Works Approvals and
detailed consultation regarding the Groundwater Licence and associated Water
Management Plan has occurred.
The approvals for Stage 2 consist of both Commonwealth and State level
approvals with engagement well advanced with all regulatory bodies. The
approvals timelines outlined in the Stage 1 PFS are considered achievable.
Stage 2 approvals are expected to consist of a SLOS underground mine,
permanent infrastructure corridor, associated infrastructure and changes to
Telfer approvals (processing of Havieron ore, Tailings Storage Facility 8
TSF8 raise to accept Havieron tailings), groundwater use at Havieron.
For Stage 2 approvals, an additional miscellaneous licence will be applied for
to secure access for an infrastructure corridor to connect Telfer and Havieron
(haul road, powerlines, water pipes). This is not considered a risk to the
timelines or project.
Classification The Ore Reserve classification is based on Indicated Mineral Resources only.
No Measured Mineral Resources are stated for this deposit. This classification
is based on geological confidence as a function of continuity and complexity
of geological features; data spacing and distribution and estimation quality
parameters including distance to informing samples for block grade estimation.
Inferred Mineral Resource material contained within the mine plan shapes were
set to zero grade and tonnes treated as internal dilution. It is the Competent
Person's view that the classifications used for the Ore Reserves are
appropriate.
Audits or reviews The Ore Reserve Update mine design and schedule was conducted by Entech Pty
Ltd, which included a review of the input assumptions. Entech found the input
assumptions to be within accepted industry practice and suitable for the level
of study.
SRK Consulting (Australasia) Pty Ltd has completed an independent technical
assessment of the 2022 Ore Reserve estimates completed by Greatland for the
Havieron gold and copper deposit. As part of that assessment, SRK reviewed the
reserve modelling methods and parameters and is of the opinion that they are
reasonable and take into consideration all of the current exploration data and
levels of technical knowledge of the Havieron deposit. SRK considers that the
Ore Reserves have been reported in accordance with guidelines and principles
outlined in the 2012 edition of the Australasian Code for the Reporting of
Exploration Results, Mineral Resources and Ore Reserves (the JORC Code, 2012
edition).
Discussion of relative accuracy/ confidence The accuracy of the estimates within this Ore Reserve is mostly determined by
the order of accuracy associated with the Mineral Resource estimate, the
geotechnical inputs and the cost factors used.
The Competent Person views the Havieron Ore Reserve a reasonable assessment of
the global estimate. Some risk and opportunity is associated with the Ore
Reserve process due to the greenfield nature of the mining component of
project, and the brownfields nature of the Telfer Mine camp, process plant,
power generation and related surface infrastructure. Remaining areas of
uncertainty at this stage are associated with:
· Cost base assumptions rely on current technology and
macroeconomic factors. Changes to these assumptions will have an impact on the
Ore Reserve estimate.
· The Modifying Factors (key inputs) for Ore Reserve estimation
rely upon the geology and geotechnical data inherent to the orebody. This
data, such as geological structures and rock mass properties, is to the
appropriate definition and has been applied within the Stage 1 PFS, however
further orebody data is required to confirm the geological and geotechnical
information and is planned as part of the Forward Works Program.
· Newcrest stated on 17 February 2022 as part of their Half Year
Results Update that the decline experienced difficulty in poor ground
conditions during the early stages. The team is working to understand the
impact on the development schedule and this may also impact on vertical
development. First production ore is expected in FY24 (rather than H1
FY24) and more updates will be provided as information comes to hand.
· Mining throughput rate is based on equipment simulation studies
considering the planned mine design and indicated that the 3 Mtpa through
rate adopted in the study is appropriate, but is considered to be at the
higher end of industry benchmark results. It is planned to be further
investigated during the Forward Works Program.
The following Modifying Factors have been applied to all mining shapes to
accurately represent the expected mined tonnes and grades:
· Dilution factors for overbreak in primary, secondary and tertiary
stopes (average 9%), consisting of waste (average 6%) and stope paste (average
3%); Dilution tonnes were estimated as an equivalent depth of failure based on
geotechnical estimations, applied to the individual stope walls and in the
respective stoping sequence, to estimate paste and waste rock volumes and
expressed here as an average percentage of the overall stope tonnes.
· Dilution included at zero grade; and
· Mining recovery factor of 97.5%, based on the near vertical
nature of the stopes, proposed mining method and geotechnical estimation of
overall stope stability.
The ultimate extent of the deposit remains open and orebody knowledge will
increase as drilling and mining progress. Current mining modifying factors
are based on known data to date and may change as new information becomes
available.
The February 2022 Resource Model is comprised of Indicated Mineral Resources
and Inferred Mineral Resources. Mine plans are based on the definition of
mining shapes only considering the contribution of metal from Indicated
Mineral Resources.
Ore Reserves estimates and statements are required to include estimates of
dilution. The dilution included in the total Ore Reserve is approximately
2.7Mt which is comprised of Inferred and Unclassified Mineral Resources, waste
host rock and paste fill dilution. Metal from the Inferred and Unclassified
Mineral Resource material was not considered in the economic assessment of the
stopes.
The Havieron Project is a greenfield mining project and will require the
following mining infrastructure to support the mine:
· decline, accesses to the levels, ore passes, ventilation raises
and other underground excavations
· paste fill plant and underground distribution system
· ventilation fans, regulators and refrigeration equipment
· dewatering, electrical distribution and other service equipment
Non-mining infrastructure is discussed in more detail under the Infrastructure
section.
Metallurgical factors or assumptions
It is anticipated that Havieron underground ore will be processed on a
campaign basis through the existing Telfer Train 2 Treatment Plant circuit at
a throughput of approximately 3 Mtpa, with tailings being disposed in the
current Telfer Tailings Storage Facility. Metal recovery is anticipated to
be through conventional flotation to produce a copper/gold concentrate and
gold doré through a newly installed flotation tails carbon-in-leach (CIL)
circuit. The technology associated with the ore processing is conventional and
the flowsheet is similar to that utilised by other operations.
Metallurgical recovery assumptions are based on detailed analysis and
laboratory flotation and leach test work completed on 38 variability samples
during the Havieron Concept Study (2020) and Stage 1 PFS (2021) with good
spatial coverage of the Crescent Zone. Of the 38 samples, 8 samples are
located in the breccia zones and 30 samples are located in the Crescent Zone,
of which 21 samples are located within the Crescent Zone Indicated Mineral
Resources. Based on these samples, average life of mine metallurgical
recoveries are estimated to be:
· gold: approximately 88%, and
· copper: approximately 84%, variable on block metal grade.
Bismuth is the key deleterious element for the gold/copper concentrate product
with smelter penalties incurred on the basis of bismuth content. It is
anticipated that the impact of bismuth in concentrate will be managed by mine
sequencing and concentrate blending.
Bulk sample or pilot scale test work has not been undertaken.
Environmental
Detailed environmental studies have been undertaken in the project area and
include flora and vegetation, fauna, subterranean fauna, waste rock
characterisation, soil and landform study, surface hydrology assessment, a
basic hydrogeological assessment and a greenhouse gas emissions study.
The Project has been designed to recognise biodiversity values and, through
consultation with Martu and their native title corporation (WDLAC), minimise
the impacts to sites and landscapes of cultural significance. The footprint
for the Project has been minimised through the use of existing tracks and
areas of disturbance, as well as utilising the existing Telfer Gold Mine
infrastructure to process the ore and dispose of the tailings material.
Waste rock characterisation has been undertaken and shows that it contains
material which has potentially acid forming (PAF) and metalliferous drainage,
in addition to dispersive or saline material. The portion of PAF material is
less than 1% of total waste volumes. Waste dumps have been designed for the
life of mine that have incorporated cells to safely encapsulate the PAF
material. The waste dump is to be located near the boxcut to minimise haulage
distance and considering the local surface terrain and environmental and
cultural aspects.
A staged approach for approvals is being undertaken, with Stage 1 currently
approved, which has allowed the development of the boxcut, decline and service
corridor. These approvals also allow for a waste rock dump, evaporation ponds
and supporting infrastructure such as offices and workshops.
Stage 2 approvals are expected to consist of a SLOS underground mine,
permanent infrastructure corridor, associated infrastructure and changes to
Telfer approvals to accept Havieron tailings in existing tailings storage
facilities.
Infrastructure
Havieron is a greenfield mining project and will require the following
infrastructure to support mining operations:
· Ventilation fans and refrigeration equipment;
· Paste plant;
· Surface Mining Infrastructure Area (MIA) including camp, offices,
workshops, evaporation ponds, electrical substations, explosive magazines,
batch plant, waste dumps, ore stockpile, and other facilities;
· Haulage road and Service Corridor to transport the ore from
Havieron to the Telfer Processing Plant and run overhead powerlines along the
Service Corridor to extend electrical power from the existing Telfer gas fired
power station to Havieron; and
· Modifications to the existing Telfer Processing plant to treat
the ore coming from Havieron.
The capital and operating costs for the above have been estimated in the Stage
1 PFS. The infrastructure estimates for this Ore Reserve Update remains in
line with the Stage 1 PFS, with additional allowance made for ventilation and
processing due to a slightly deeper ultimate depth and in line with the
expanded mine plan.
Access to Telfer Mine is already in place via the Telfer Access Road. Telfer
Mine has an existing camp, sealed runway and airport, gas-fired power station
and processing plant.
Costs
Capital and operating costs underlying assumptions are to a PFS level. Capital
cost estimates are based on multiple market prices across all technical
disciplines and include processing upgrade and mine development costs along
with associated surface and underground infrastructure, project establishment
and sustaining capital costs. These provisions have been allowed for during
the life of the mine based on the Stage 1 Study estimates. Contingency has
also been factored into the project capital cost estimate consistent with the
level of accuracy of the study.
Newcrest stated on 17 February 2022 as part of their Half Year Results Update
that the decline experienced difficulty in poor ground conditions during the
early stages. The team is working to understand the impact on the
development schedule and this may also impact on vertical development. First
production ore is expected in FY24 (rather than H1 FY24) and more updates
will be provided as information comes to hand.
The operating cost estimates are in line with the Stage 1 PFS, which were
sources from current Telfer rates and contractor schedule of rates submitted
for PFS budget purposes and are inclusive of:
· mining cost: development by drive type and ground support
profile, longhole drilling and blasting, haulage for ore and waste, labour,
maintenance and other fixed costs
· electrical power cost based on estimated power consumption and
supply from Telfer Power Plant
· surface transport cost to Telfer Processing plant
· processing cost and
· relevant site general and administration costs.
Ore Reserve cost estimates have been independently reviewed and are considered
to be at an appropriate level for a PFS.
The Stage 1 PFS transport and refining charges have been developed from first
principles consistent with the application of the current Telfer operation.
These included charges for deleterious elements, e.g. bismuth where
applicable. These assumptions and estimates were carried forward into the
February 2022 Update.
Costs include a revenue-based payment from mining the Havieron Project area
under the ILUA with WDLAC.
State royalties are 2.5% for gold, 5% for copper after allowable deductions.
Revenue factors
Long term metal prices and exchange rate assumptions adopted for estimating
this Ore Reserve Update are US$1,450/oz for gold, US$3.23/lb for copper, at a
USD:AUD exchange rate of 0.73. Commodity prices and exchange rate forecasts
were based on the Median Long Term price forecasts, as sourced from Consensus
Economics and Bloomberg. These price assumption are higher than the
US$1,300/oz for gold and US$3.00/lb for copper and USD:AUD exchange rate of
0.75 assumed for the October 2021 Stage 1 Study, but were selected in line
with median long term consensus price forecasts and historical metal prices
over the past 5 years.
An NSR value calculation was adopted, taking into account Ore Reserve revenue
factors, metallurgical recovery assumptions, transport costs and refining
charges and royalty charges.
Market assessment
Gold will be sold on the open market and subject to price fluctuations. Supply
and demand for gold from Telfer and Havieron is not considered a constraint in
the estimation of the Ore Reserve.
Telfer has sold copper concentrate for its operational life into the world
concentrate markets and this is assumed to continue under conditions similar
to Newcrest's current market agreements over the life of the operational plan.
Concentrate volume forecasts were derived from the Updated Ore Reserve
production schedule.
Economic
The Ore Reserve has been evaluated through a financial model on a real
cashflow basis. All operating and capital costs as well as revenue factors
stated in this document were included in the financial model. A discount
factor of 4.5%pa real was applied. This process demonstrated the Havieron Ore
Reserve to have a positive NPV at current assumptions.
Sensitivities were conducted on the key input parameters including commodity
prices, capital and operating costs, ore grade, mined tonnes, exchange rate
and metallurgical recoveries confirming the estimate to be robust.
Social
The traditional landowners, the Martu people and the WDLAC are key project
stakeholders. The Martu hold exclusive possession native title rights and
interests over more than 130,000km(2) of land, including to all points around
the Telfer mine and Havieron Project. The ILUA with WDLAC, centred on the
Telfer mine, extends to the Havieron Project.
Other
The only identified material naturally occurring risk at Havieron is flooding
from large rain events typically associated with the cyclone season. The
existing boxcut has been located and all other surface connections to the
surface have been designed above a modelled 1 in 1,000 year Average Recurrence
Interval (ARI) event where possible, or will be elevated such that large
volumes of water cannot enter the mine workings.
A number of State and Commonwealth statutory requirements are relevant to the
Havieron Project and all aspects of the Project will comply with the relevant
Government Acts and Regulations applicable in the jurisdiction of Western
Australia.
Approvals
A Mining Lease has been granted over the orebody, and miscellaneous licence
granted along the existing service corridor.
A staged approach for approvals is being undertaken with Stage 1 currently
approved which has allowed the development of the boxcut, decline and service
corridor. These approvals also allow for a waste rock dump, evaporation ponds
and supporting infrastructure such as offices and workshops. Minor additional
approvals are in the process of being obtained and include a Groundwater
Licence amendment and Part V approval to allow the operation of the
evaporation ponds, waste water treatment plant and to allow construction of a
landfill for non-mineralised waste.
The Part V licence and registrations have approved Works Approvals and
detailed consultation regarding the Groundwater Licence and associated Water
Management Plan has occurred.
The approvals for Stage 2 consist of both Commonwealth and State level
approvals with engagement well advanced with all regulatory bodies. The
approvals timelines outlined in the Stage 1 PFS are considered achievable.
Stage 2 approvals are expected to consist of a SLOS underground mine,
permanent infrastructure corridor, associated infrastructure and changes to
Telfer approvals (processing of Havieron ore, Tailings Storage Facility 8
TSF8 raise to accept Havieron tailings), groundwater use at Havieron.
For Stage 2 approvals, an additional miscellaneous licence will be applied for
to secure access for an infrastructure corridor to connect Telfer and Havieron
(haul road, powerlines, water pipes). This is not considered a risk to the
timelines or project.
Classification
The Ore Reserve classification is based on Indicated Mineral Resources only.
No Measured Mineral Resources are stated for this deposit. This classification
is based on geological confidence as a function of continuity and complexity
of geological features; data spacing and distribution and estimation quality
parameters including distance to informing samples for block grade estimation.
Inferred Mineral Resource material contained within the mine plan shapes were
set to zero grade and tonnes treated as internal dilution. It is the Competent
Person's view that the classifications used for the Ore Reserves are
appropriate.
Audits or reviews
The Ore Reserve Update mine design and schedule was conducted by Entech Pty
Ltd, which included a review of the input assumptions. Entech found the input
assumptions to be within accepted industry practice and suitable for the level
of study.
SRK Consulting (Australasia) Pty Ltd has completed an independent technical
assessment of the 2022 Ore Reserve estimates completed by Greatland for the
Havieron gold and copper deposit. As part of that assessment, SRK reviewed the
reserve modelling methods and parameters and is of the opinion that they are
reasonable and take into consideration all of the current exploration data and
levels of technical knowledge of the Havieron deposit. SRK considers that the
Ore Reserves have been reported in accordance with guidelines and principles
outlined in the 2012 edition of the Australasian Code for the Reporting of
Exploration Results, Mineral Resources and Ore Reserves (the JORC Code, 2012
edition).
Discussion of relative accuracy/ confidence
The accuracy of the estimates within this Ore Reserve is mostly determined by
the order of accuracy associated with the Mineral Resource estimate, the
geotechnical inputs and the cost factors used.
The Competent Person views the Havieron Ore Reserve a reasonable assessment of
the global estimate. Some risk and opportunity is associated with the Ore
Reserve process due to the greenfield nature of the mining component of
project, and the brownfields nature of the Telfer Mine camp, process plant,
power generation and related surface infrastructure. Remaining areas of
uncertainty at this stage are associated with:
· Cost base assumptions rely on current technology and
macroeconomic factors. Changes to these assumptions will have an impact on the
Ore Reserve estimate.
· The Modifying Factors (key inputs) for Ore Reserve estimation
rely upon the geology and geotechnical data inherent to the orebody. This
data, such as geological structures and rock mass properties, is to the
appropriate definition and has been applied within the Stage 1 PFS, however
further orebody data is required to confirm the geological and geotechnical
information and is planned as part of the Forward Works Program.
· Newcrest stated on 17 February 2022 as part of their Half Year
Results Update that the decline experienced difficulty in poor ground
conditions during the early stages. The team is working to understand the
impact on the development schedule and this may also impact on vertical
development. First production ore is expected in FY24 (rather than H1
FY24) and more updates will be provided as information comes to hand.
· Mining throughput rate is based on equipment simulation studies
considering the planned mine design and indicated that the 3 Mtpa through
rate adopted in the study is appropriate, but is considered to be at the
higher end of industry benchmark results. It is planned to be further
investigated during the Forward Works Program.
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