REG - Metminco Limited - Maiden Ore Reserve for Miraflores - Update <Origin Href="QuoteRef">MNC.AX</Origin> - Part 2
27/11/2017 07:40
- Part 2: For the preceding part double click ID:nRSa5605Xa
throughout the breccia. In the case of the white breccia, the polymictic breccia was moved, broken and invaded by the quartz
-calcite infill, which intheporphyryveinletclassificationsbelongtothe'E'stage(Tobey,2012).Younger sub-vertical mineralised
faults (veins) SSE - NNW and SE - NW, dipping from 75° to 90° that cross cut the breccia, represent a late event that are
characterised by a high content of sulfides (chalcopyrite, pyrite, galena and sphalerite), and high gold grades. These
structures could have acted as the feeders of the mineralisation to the breccia where the pre-existing porosity and permeability
have played an important role in the mineralizationcontrol.At 200 to 300 m depth, high gold grade mineralisation in the cement
and matrix of the breccia is found, possibly associated with a boiling zone. This is an irregular zone of 60 m
width.Mineralisation at Miraflores is contained within the Miraflores magmatic-hydrothermal breccia body and in the basalts
close to the contact. At surface, the breccia is exposed on a 30° slope, which has been worked by informal miners using
artisanal methods in small excavations and irregular tunnels. The prospect is well known for free native gold and silver
occurring in vugs and cavities in the carbonate and quartz cement of the breccia. Drilling has shown that gold mineralisation
occurs in all types of breccias in the cement and matrix.At least two mineralising events before formation of the epithermal
breccia have been observed in the fragments of the breccia. Locally, basalt clasts with veinlets of 'B' style (comb quartz
without alteration halo) cut by pyrite-epidote cracks are evidence of a possible porphyry style mineralisation preceding the
breccia formation. In the case of the white breccia, the polymictic breccia was moved, broken and invaded by the quartz-calcite
infill, which in the porphyry veinlet classifications belong to the 'E' stage (Tobey,2012).In the White Breccias sulfide
minerals occur throughout the quartz and calcite stages, and are often concentrated on epidote at the start of the quartz phase,
and are also commonly euhedral in quartz vugs. The sulfides are euhedral and coarse grained (2 to 4 mm). The percentage of
sulfides is low. The sulphides seen are pyrite, chalcopyrite, molybdenite, galena and sphalerite (honey-colored,
Zn- rich). Rare visible gold can occur invugs.Low grade gold mineralisation is found in a halo around the breccia pipe in the
basalts, and is characterised by quartz-calcite veinlets with low content of sulfides (pyrite, galena, sphalerite)
controlledbythedensityoffracturingcreatedbytheformationofthebreccia.The mineralisation in breccias and in the basalt is
characterised by low contents of chalcopyrite, sphalerite and galena, occurring as fine grains (<100 µm).The younger sub
-vertical veins SSE - NNW and NW - SE, dipping from 75° to 90° that cross cut the breccia, are characterised by argillized
material that contain important quantities of sulfides pyrite, chalcopyrite, sphalerite and galena. Some visible gold has been
observed. The sulfides are present as coarse particles ranging from 100 to 200 µm and greater than 200 µm. The persistence of
the SSE- NNW structures is important and is clearly recognised in the exploitation workings of the AMM where high gold grade
mineralisation can be followed by more than 150 m in horizontal and more than 80 m in vertical, with almost no displacement of
the structures. Crossing of structures (veins) are forming
highgoldgradeshootsofvariabledimensionsthatcanbeobservedintheAMMworkings. The Mineral Resource estimate for the Miraflores
deposit reported on 14 March 2017 was used as the basis for the conversion to an Ore Reserve. The Mineral Resource model was
delivered to Ausenco through a data fileThe resource model for Miraflores was constructed with Vulcan software using a block
model. All of the required information about the deposit is stored in each individual block. This includes estimated
characteristics of gold and silver and statistical characteristics such as number of samples used in an estimate, distances to
the nearest sample, number of drill holes used, etc., are stored in each individual block. Geologic triangulations were also
used to identify the rock type of each block, and these structures also controlled the sub-blocking in Vulcan along their
boundaries. Geologic codes stored in the block model were also used to assign the density within specific geologic boundaries.
Final geologic codes were applied to the block model using indicator kriging. Indicator kriging provides a very good check
against the implicit models derived with Leapfrog. This methodology estimates the probability that any block is a certain rock
type based on the geologic information identified in drill hole logging. The volumes derived from the indicator kriging were
nearly identical to the volumes identified with Leapfrog. So in keeping with generally accepted practices rock units were
applied using indicator kriging. Blocks identified as breccia, basalt and saprolite were estimated only using samples also
identified as the same. Samples within the modelled veins were not used to estimate grade within the breccia, basalt or
saprolite. Samples within the veins were limited to the vein the samples correlated with and only used to estimate grades
within that specific vein. Samples within the breccia, basalt and saprolite but outside the veins were not used to estimate
grade within the veins. For example: only samples flagged in vein 800 were used to estimate blocks within vein 800 and only
samples flagged as breccia were used to estimate blocks within the breccia boundary. Inverse distanced cubed grade estimation
methodology was used to estimate gold and silver grades for Miraflores. For the breccia, basalt and saprolite variography was
done to determined proper search ellipsoid orientation and search distances. The Miraflores Measured and Indicated Mineral
Resources are reported at a gold cut-off grade of 1.20 g/t Au. The resources are based on 25,884mof drilling in 73 diamond
drill holes and 236m of underground channel samples. This includes 3,624m in 10 holes carried out by AngloGold Ashanti and
B2Gold in 2006-2007. Statistical and visual checks were performed by Metal Mining Consultants of the estimated block model to
ensure there were no discrepancies in the grade estimation routines and to ensure the geometry of mineralisation meets the
configuration that the geologists expected for estimated mineralisation. Measured Mineral Resources; 2.96Mt @ 2.98g/t Au and
2.48g/t AgIndicated Mineral Resources; 6.31Mt @ 2.74g/t Au and 2.90g/t AgMeasured and Indicated Mineral Resources; 9.27Mt @
2.82g/t Au and 2.77g/t AgInferred Mineral Resources; 0.49Mt @ 2.36g/t Au and 3.64g/t Ag The Mineral Resources are reported
inclusive of the Ore Reserves. Artisanal miners have caused ore depletion within the Miraflores Project mining footprint. The
Mineral Resource Estimate used as the base for the Ore Reserve estimate incorporates this ore depletion. The Ore Reserve
estimate has relied on the accuracy of the Mineral Resource Estimate.
Site visits Comment on any site visits undertaken by the Competent Person and the outcome of those Mr Boris Caro visited the site in August 2017 for 3 days as part of the study team to review all aspects of the study including CPs
visits. an investigation of the mine, plant and site layouts. The site visit involved field work on the project footprint area including
If no site visits have been undertaken indicate why this is the case. an inspection of the underground tunnels and artisanal miners workings. Consultants involved in the mining study, metallurgical
testwork, geotechnical and geological mapping, infrastructure study, social and environmental studies all visited the site
during this time.
Study status The type and level of study undertaken to enable Mineral Resources to be converted to Ore Reserves. A feasibility study has been completed for the Miraflores Project. Metminco engaged GE Engineering Services to complete the Metminco
The Code requires that a study to at least Pre-Feasibility Study level has been undertaken processing, infrastructure and feasibility study management aspects of the feasibility study. Ausenco Chile were engaged to
to convert Mineral Resources to Ore Reserves. Such studies will have been carried out and complete all aspects of the mine design, mine scheduling, geotechnical analysis and ventilation system design to support the
will have determined a mine plan that is technically achievable and economically viable, mine design, including capital and operating costs for the mine. Surface geotechnical design for the plant, infrastructure and
and that material Modifying Factors have been considered. tailings facility was undertaken by Dynami Geo Consulting (a Medellin based consulting company) and Grana y Montero Engineering,
a Lima, Peru based engineering and contracting group assisted in the design of the Tailings Storage Facility. This study
provided sufficient technical and economic support to back up the Ore Reserve estimate.
Further analysis and test work is recommended for the stope filling sequence and stability analysis prior to any decision to
commence with the project construction.
Cut-off parameters The basis of the cut-off grade(s) or quality parameters applied. An underground cut-off grade (CoG) of 1.53 g/t for gold was applied to underground diluted resources constrained by the final AUSENCO
underground design. This grade delineated the Ore Reserve estimate.* Reserves are based on a gold price of US$1,200/oz;
* Reserves are defined within an underground mine plan generated from diluted Measured and Indicated Mineral Resources;
* An underground CoG of 1.53 g/t Au was applied to underground resources constrained by a final underground design;
* Underground reserves assume 20% planned and 11% unplanned dilution;
* In-situ Au ounces disregard metallurgical recovery of 92%;
* 28% of the mined out stopes and drifts will use backfill including waste and filtered tailings material. Backfilling
- More to follow, for following part double click ID:nRSa5605XcRecent news on Merino & Co
See all newsREG - AIM Metminco Limited - Cancellation - Metminco Limited
AnnouncementREG - FTSE Metminco Limited - Metminco
AnnouncementREG - Metminco Limited - Change in Substantial Shareholding
AnnouncementREG - Metminco Limited - AIM delisting and Share Registry update
AnnouncementREG - Metminco Limited - Capital Raising
Announcement