Toronto-based explorer Atacama Pacific Gold (ATM-V) has had a good run over the past four weeks. Anticipation built as Atacama neared completion on a year-long resource drill program at its wholly owned Cerro Maricunga gold property, 140 km northeast of Copiapo, Chile. The payoff arrived on Sept. 25, when the company unveiled a 65% increase in oxide-associated, measured and indicated resources at the project.
Atacama’s third-phase drill program, which concluded in June, covered 45,000 metres and carried a US$24.5-million price tag. The company focused on expanding resources along strike and to depth, and tested a series of new targets. Atacama's second phase of drilling outlined oxide-hosted gold mineralization over three zones that covered 2.5 km of a northwest to southeast trend that crosscut the Cerro Maricunga volcanic complex.
The company was hoping to expand its Crux gold zone, located on the deposit’s southern reaches. The drill program extended total width to 450 metres, and increased the mineralization depth to the northeast — an area Atacama had previously believed was unmineralized.
Additional drilling focused on delineating the company’s Phoenix and Lynx zones to boost geological confidence in the deposit, and extend mineralization along its strike length. Atacama reported that infill results at Phoenix-Lynx came "largely as anticipated, confirming the continuity of gold mineralization."
Atacama has also been working on targets established at Pollux, a newly discovered gold zone east of Phoenix. The company cut 11 holes and established a 400-metre strike length at Pollux during its 2012 program, and suspects the zone may represent mineralization between Phoenix and Crux that is displaced to the northeast by faulting.
A gold zone was also discovered 600 metres northeast of Phoenix, where hole 190 returned 90 metres grading 0.49 gram gold per tonne.
Atacama’s resource program boosted total resources at Cerro Maricunga to 164 million measured and indicated tonnes averaging 0.51 gram gold, for 2.7 million contained oz. gold at a 0.3 gram gold cut-off grade. The project carries an additional 121 million inferred tonnes grading 0.47 gram gold, for 1.8 million contained oz. gold.
"The release of our [estimate] confirms that the Cerro Maricunga property hosts one of the largest oxide gold deposits in the world not owned by a gold producer," president and CEO Carl Hansen states, adding that "the large oxide resource and remarkable continuity of the gold mineralization, combined with excellent metallurgical recoveries, suggest that Cerro Maricunga has the potential to be an attractive development project."
Hansen speculates on the potential for a heap-leach operation with a throughput rate of 60,000 to 80,000 tonnes per day, and says the company expects a preliminary economic assessment before the new year. In January 2012, Atacama released results from eight column-percolation leach tests that indicated gold recoveries from oxide materials ranging from 77% to 86%.
The Lynx and Phoenix zones account for 73% of Atacama’s measured and indicated resources. Average grades fell from 0.54 gram gold to 0.51 gram gold due to lower-grade mineralization from Pollux and Crux. Pollux added 11 million measured and indicated tonnes grading 0.46 gram gold, for 162,000 contained oz. gold.
Atacama reported US$29 million in working capital at the end of June, and has planned a fourth drilling phase in November that exceeds 20,000 metres. The program will upgrade inferred resources and test exploration targets.
Atacama has surged 43%, or $1.05 per share since August, en route to a $3.50 press-time close. The company has traded within a 52-week range of $2.21 and $5.51 per share, on the back of average daily trade volumes of 135,000 shares.
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