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REGIONAL NEWS - LATIN AMERICA Core storage and processing facilities at Atacama Pacific's Cerro Maricunga gold project in northern Chile. Capital cost to develop the open-pit mining project is estimated at $514.6 million. (Photo courtesy Atacama Pacific) Capital cost to develop the project is estimated at $514.6 million, with sustaining capital of $249 million. The Cerro Maricunga project is located in the high Andes 140 km northeast of Copiapo, Chile, and 40 km west of the Chile-Argentina border at elevations ranging between 3,800 and 5,000 m above sea level. The PEA is based on a pit-constrained resource estimated at 185.8 million mt measured and indicated grading 0.41 g/mt gold and containing 2.46 million oz of gold and 75.4 million mt inferred grading 0.39 g/mt gold and containing 938,000 oz of gold. Conventional open-pit mining methods are considered for mining the Cerro Maricunga deposit, utilizing a fleet of 16 haul trucks (Komatsu 9300E – 290 mt), five diesel shovels (Komatsu PC5500 – 38 yd3), five production drills (Sandvik DR460 – 10 5/8 in.), and various ancillary equipment. No additional production fleet equipment is considered during the mine life. The preliminary open-pit design incorporates 10-m-high benches, with 40-mwide main haul roads at a maximum grade of 10% and pit walls at an average 42° angle. The PEA envisions trucking of oxide mineralization to a primary gyratory crusher, with a minimum capacity of 4,200 mt/hr, where it will be crushed to 165 mm. The primary crushed material will then be conveyed 3.4 km to feed three secondary cone crushers and three tertiary cone crushers. The final crushed product, measuring (P80) 19 mm, will be conveyed 2.8 km to the heap leach pads. 22 E&MJ; • APRIL 2013 Crushed material will be stacked on the pads by a radial stacker in 50 x 50-m modules in layers 10 m thick. Every five layers, a geomembrane will be placed on the heap to separate subsequent layers from the underlying material. The final leach pad height will be approximately 100 m. A pad irrigation rate of 10 liters/hr/m2 is considered. Sodium cyanide and lime consumption are expected to be 0.24 kg/mt and 1.4 kg/mt, respectively. The pregnant leach solution will be pumped to a conventional carbon adsorption facility, where gold will be recovered to a final gold doré product. Average gold recoveries of 79.5% were considered in the PEA based on bottle roll and column metallurgical testing. Atacama Pacific President and CEO Carl Hansen said, "With the PEA completed, we will move toward a feasibility study and will examine the opportunities to potentially improve the results of the PEA by increasing the overall resource through additional drilling and by leaching coarser crushed material in a valley-fill heap leach scenario." Vista Reports Positive PEA for Guadalupe de los Reyes Vista Gold has reported positive results from a preliminary economic assessment (PEA) of its Guadalupe de los Reyes gold-silver project in Sinaloa, Mexico. The PEA evaluates the potential viability of a 1,500-mt/d processing facility producing a total of 327,681 oz of gold and 4.39 million oz of silver over an 11-year mine life, including average payable production of 35,031 oz/y gold and 253,223 oz/y silver over the first five years. Gold and silver recoveries are estimated at 93% and 83%, respectively, through a conventional CIL recovery circuit. Goldequivalent cash costs are estimated at $631/oz over the life of the mine, including average gold-equivalent cash costs of $568/oz over the first five years. Initial capital costs are estimated at $88.9 million, and life-of-mine capital costs are estimated at $124.3 million. Capital payback is estimated at 3.6 years using gold and silver prices of $1,480 and $28/oz, respectively. Vista President and CEO, Fred Earnest, said, "This PEA demonstrates the potential for a small but profitable project with low estimated initial capital requirements… The completion of the PEA culminates a successful step in the evaluation of Guadalupe de los Reyes, which we believe represents an interesting opportunity to potentially initiate operations with a smallscale, open-pit mining operation that would provide cash flow from operations to continue exploring for high-grade mineralization at depth. "We have completed and published the results of this PEA as we indicated to the market we would do last year; however, our focus remains on completing the preliminary feasibility study on the Mt. Todd project in Northern Territory, Australia," said Ernest. "For the remainder of 2013, Vista's expenditures on the Guadalupe de los Reyes project will be restricted to property holding costs and community support initiatives, as the company remains primarily focused on the continued evaluation of the Mt. Todd project." Panterra's Las Lagunas Continues to Improve Officials at PanTerra Gold announced ongoing improvements at their Las Lagunas gold and silver project in the Dominican Republic. Management is seeing plant feed, metal grades, grinding circuit performance and flotation circuit recoveries which now are closer to meeting design targets. An Albion oxidation circuit is also expected to reach design levels with CIL recoveries expected improve. PanTerra CEO Brian Johnson, who was part of the review team, expressed confidence in the project's success. "Previous feed rates and quality, as well as plant operations, were erratic for eight months following construction completion; only since the beginning of March has the plant been able to be operated without significant interruption," he said. www.e-mj.com