Photo by: Newstrike Capital
TORONTO (miningweekly.com) – Mexico-focused Newstrike Capital on Thursday revealed that a column leach metallurgical result from a composite sample supported heap leach extraction potential within the low-grade breccia zone at its flagship Ana Paula gold project, located in Guerrero state, Mexico.
Despite the project’s sulphide ore in general not being amenable to heap leaching, tests conducted by Tucson, Arizona-based consulting engineers SGS Metcon/KD Engineering confirmed that significant gold recoveries at 84.1% were obtained from a representative composite sample from two drill holes, AP-11-36 and AP-13-213, selected from within the project’s maiden resource floating cone pit.
The sample was chosen to test the leaching ability of the low-grade breccia zone, a predominantly intrusive unit located in the south-west portion of the floating cone pit and separate from the high-grade breccia zone.
Composite 4 was taken from a sample of altered intrusion that had not yet been fully delineated by drilling and displayed a level of oxidation greater than compared with most of the Ana Paula deposit.
The sample was prepared from 56.28 m of drill core, weighing about 88 kg when submitted for metallurgical testing.
Newstrike CEO Richard Whittall said while the company’s 2013 metallurgical testing programme had confirmed a conventional, low-risk approach at Ana Paula, with strong gold recoveries, this specific column leach result added an “extremely encouraging new dimension to the project”.
“Heap leaching has the potential to lower processing costs and provide an additional source of revenue through the recovery of gold from our mineralised waste. We plan to investigate the size and scope of this opportunity within Ana Paula's floating cone pit and the potential for a reduction in the strip ratio and expansion of the conceptual pit.
“Combined with last year's testing, this new metallurgical result will provide valuable input to the preliminary economic assessment currently in progress as well as for future studies,” Whittall said.
The testwork concluded that most of the gold was extracted in the first ten days of being placed on the pad and that the maximum extraction achieved was 84.1% on Composite 4.
Newstrike also said the testwork indicated a low sodium cyanide consumption rate at 0.19 kg/t and moderate lime consumption at 3.62 kg/t. Good gold and silver extraction correlations were observed between the results from the bottle-roll testing and the column-leach testing. Further Bond Impact Crusher Work Index and Bond Abrasion Index studies would be conducted on Composite 4.
The news pushed Newstrike’s TSX-V-listed stock up by a penny to C$0.85 apiece on Thursday.