New Gold owns a 100% interest in the Pedra Branca do Amapari (“Amapari”) Mine through its wholly owned subsidiary Mineracao Pedra Branca do Amapari (“MPBA”)
Amapari was built during 2005-2006 as an open-pit, heap leach operation. Since production start-up in 2005, a total of approximately 6.4 million tonnes of ore grading 2.26 grams per tonne were processed.
Historically, the operation has utilized conventional open-pit mining techniques and heap leaching to exploit the gold resource at Amapari. Soft, gold-bearing saprolitic ores were excavated by backhoes, without prior blasting and then hauled to the process facility. Ore was passed through primary and secondary MMD roll crushers and crushed to a size of – 1 inch prior to being agglomerated with cement and stacked in 6 m lifts on one of four “On-Off” heap leach pads. The stacked ore was sprinkled with dilute cyanide solution over a typical leaching cycle of 110 days, after which the material was reclaimed by a bucketwheel excavator and conveyed to a “Spent Ore” stockpile. After leaching, gold was removed from the resulting “pregnant” solution in a standard “ADR” plant using carbon column and electrowinning technology.
On January 2, 2009, New Gold announced the suspension of mining at Amapari and stated that the mine was being placed on care and maintenance. The main reason for the suspension of operations was the increasing occurrence of hard “transitional” ore which forms between the weathered saprolite and the underlying, unweathered, sulphide ore. This transition material occurred earlier in the mine life than was projected and was becoming pervasive in all mining areas. The transition material cannot be excavated without blasting, nor effectively crushed in the MMD roll crushers, which are not designed for hard material. The relatively small, remaining oxide (plus transition) resource does not warrant the capital expenditure that would be required to process this material through the existing facility.
AMC Mining Consultants (Canada) Ltd (AMC) has completed a Scoping Study to assess the potential for mining of sulfide mineral resources and the remaining oxide mineral resources with a new project involving the construction of a two stage ball mill and carbon-in-leach (“CIL”) processing plant. Mining of the sulfide mineral resources has not previously been evaluated in a pre-feasibility study or feasibility study. The AMC’s Scoping Study examined the potential for mining of the sulfide and the remaining oxide mineralization via a combination of open pit and underground mining and processing by conventional milling and a CIL plant.