Feb 18 2011
Atacama Pacific Gold Corporation (TSX VENTURE:ATM) has reported continued positive drill assay results from the Phase II exploration program underway on its 100%-owned Cerro Maricunga Gold Project, located 140 kilometres northeast of Copiapo, Chile.
The nine drill holes returned significant intervals of +0.3 gram per tonne gold ("g/t Au") mineralization hosted within oxidized breccias extending to depths in excess of 450 metres.
Assay highlights, at a 0.3 g/t Au cut-off, from the current drilling program include:
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CMR-025 (Phoenix Zone) - 254 metres of 0.57 g/t Au and 146 metres of 0.55 g/t Au
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CMR-028 (Phoenix Zone) - 208 metres of 0.60 g/t Au including 44 metres of 1.00 g/t
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CMR-022 (Lynx Zone) - 76 metres of 0.77 g/t Au including 30 metres of 1.13 g/t
Phoenix drilling, which targeted the core and the northeast contact of the zone, continued to intersect wide zones of low to moderate grade gold mineralization. Along the northeast contact, significant intervals of lower grade gold mineralization, in the 0.2 to 0.3 g/t Au range, were encountered as halos surrounding higher grade zones. For example, the entire 444 metre length of CMR-025 returned 0.53 g/t Au when composited using a cut-off grade of 0.2 g/t Au. The last four metres of CMR-025 graded 0.96 g/t Au.
Along the Lynx Zone, drill hole CMR-022 returned 76 metres grading 0.77 g/t Au including a higher grade interval of 30 metres grading 1.13 g/t Au. A lower grade interval of 0.42 g/t Au over 30 metres was encountered closer to surface. CMR-022 traced the Lynx Zone a further 100 metres along strike towards the Phoenix Zone and extended the oxide associated mineralization to a depth of 300 metre below surface. The mineralization and zone of oxidization remains open to depth.
"We continue to be very pleased with the drill results from Cerro Maricunga", stated Carl B. Hansen, President and CEO of Atacama Pacific, "as they further establish the continuity of the large oxidized, breccia-hosted gold system extending over a strike of 2.5 kilometres and to depths in excess of 450 metres. Four drill rigs are presently operating on the property with two rigs targeting the 400 metre wide Phoenix Zone and the other two drills tracing the gold mineralization from the Lynx and Crux Zone towards the Phoenix Zones. We look forward to our initial resource estimation on Cerro Maricunga, planned for the third quarter of 2011."
Three drill holes, collared along the north westerly trending extension of the Crux Zone, encountered +0.3 g/t Au mineralization extending over a strike length of 500 metres with true widths of +20 metres. Drill hole CMR-016 was collared into 40 metres grading 0.79 g/t Au and a second hole has been drilled in the opposite direction to determine the width of the gold zone. Significant halos of 0.2 to 0.3 g/t Au mineralization were also encountered.
Metallurgical Results – Preliminary Comminution Tests
Crushing and grinding of ore is a significant capital and operational cost in many mineral processing plants. As such it is important to fully determine the comminution parameters relevant to the crushing of the Cerro Maricunga gold mineralization in order to determine potential cut off grades and to assist in plant design.
Two samples of gold mineralized material were tested to determine: 1) the work index, the amount of energy, measured in kilowatt hours per tonne ("kWhr/t"), required to grind the host rock; and, 2) the bond abrasion index, to determine abrasiveness of the mineralized material.
The Work indices were low varying from 10.63 to 11.26 kWhr/t suggesting relatively low power requirements for crushing. The work index was determined from ball mill grindability tests conducted at 100 mesh (150 µm).
The abrasion tests returned low (0.067) to moderate (0.124) Bond Abrasion indices, averaging 0.095. Material with a Bond Abrasion Index of less than 0.1 has relatively low abrasiveness to processing equipment. Abrasion indices were conducted on a -3/4" + 1/2" fraction of crushed samples.
The reported test work was completed by metallurgical testing and consulting services firm Phillips Enterprises, LLC of Golden, Colorado. Atacama Pacific's metallurgical testing program is managed by AMTEL (Advanced Mineral Technology Laboratory Ltd), London, Canada.
Source: Atacama Pacific Gold Corporation