** Shares of mineral exploration co Gateway Mining Ltd
GML.AX rise as much as 8.3% to A$0.013
** Stock set for its best day since March 29, if gains hold
** GML says it has entered into an agreement with a unit of
Rio Tinto RIO.AX and DiscovEx Resources DCX.AX , which gives
the Rio Tinto unit the option to acquire the iron ore rights of
two tenements of DiscovEx's Sylvania Project urn:newsml:reuters.com:*:nASX2t8Vlz
** Gateway, which holds royalty over the tenements, to
receive up to A$120,000 in option payments from the Rio Tinto
unit
** Stock down 7.7% this year, as of last close
(Reporting by Anan Ashraf)
((Anan.Ashraf@thomsonreuters.com;))