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Jul 2012 - MacPhersons Res

MacPhersons Resources Ltd (MRP) –Bringing the Nimbus Silver Mine back into Production

  • MacPhersons Resources Limited (MRP) changed direction (from developing the MacPhersons Reward and Tycho gold mine assets) in mid-2011 with the acquisition of the Nimbus Silver mine and its mothballed operational facilities in mid-2011, and later the adjacent Boorara goldfield, all only ~10km east of the Kalgoorlie Super-pit in WA.
  • The geology at Nimbus is very different to the standard "Kalgoorlie geology", being either a VMS or high sulphidation epithermal system. Following an exploration programme, MRP has reinterpreted and consequently remodelled the geological understanding and model of Nimbus into two main NW/SE brecciated ore-bearing shoots, and is in the process of grid - RC drilling the property to identify further possibly overlooked shoots or lodes.
  • A new resource is expected to be reported in DQ 2012, along with the completion of the metallurgical route (direct to Merrill Crowe or flotation to a concentrate), of which the Merrill Crowe route (with by-product credits) appears the most likely as it could also treat the Boorara goldfield ore. After which the existing plant can be modified and upgraded.
  • Production could theoretically start in MQ 2013 treating 180,000tpa for a short period of time. However, the key requirement for Nimbus' future is the approval of a new TSF (tailings storage facility) capable of allowing 480,000tpa to be treated, and that could take 6 to 12 months to be approved in WA, which could delay the production start to SQ 2013.
  • Aside from the treatment rate, just how much silver is going to be produced per year is a function of the grade. The previous producer (Polymetals in ~2004) used a bottom cut or cut-off grade of 100g/tAg, and treated ore at ~410g/tAg plus low grade at ~95g/t for an average head grade of ~350g/tAg. Treatment of 480,000tpa at 100g/tAg could be 1.5mozpaAg per year, or possibly 1.4mozpaAg at an ~90% recovery. At 300g/tAg, it could become ~4.2mozpaAg.
  • And then there is the Boorara Goldfield, plus the existing gold mine assets of MacPhersons Reward and Tycho in MRP's original Coolgardie Gold Project (on which MRP listed). Consisting mostly of stockwork mineralisation near surface, Boorara was mined by open-cut and underground, whereas MacPhersons Reward and Bakers Find were open-cuts, with Tycho as a prospect, although all are on granted MLs.

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Jul 2012 - MacPhersons Resources Ltd

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  • Written by: Keith Goode
  • Sunday, 01 July 2012