Vancouver —
A former underground mine, Cozamin is 4 km from Zacatecas city and sits at an elevation of 2,400 metres on the Mexican plateau between the Sierra Madre Oriental and Sierra Madre Occidental.
Three of the four latest holes drilled from surface on the Mala Noche vein in the San Roberto sector of Cozamin yielded significant results. The intercepts occurred between depths of 190 and 355 metres. The Mala Noche mesothermal vein system showed comparable grades 500 metres away from the workings.
“So far, the vein has been mapped on surface for more than five and a half kilometres where it varies from five to eight metres wide,” says Capstone President Darren Pylot. “There are old workings all along the vein, but the San Roberto sector near the mill is where production occurred. Our drilling focused on one and a half kilometres of the strike length of the vein and then stepped out another five hundred metres (in hole 20) for a total of two kilometers so far.”
Hole 18 returned a 14.1-metre-wide intercept grading 3.9% copper, 0.4% zinc and 82.2 grams silver per tonne; included was a 6.4-metre section of 7% copper and 145.6 grams silver. The hole confirmed the vein’s width and grade in the eastern part of the zone, where hole 3 returned 4.35% copper and 99.6 grams silver over 14.9 metre (true width) and hole 10 returned 2.5% copper and 107 grams silver over 9 metres.
Other highlights from this vein include 3.9 metres grading 1.5% copper, 0.5% zinc and 62.2 grams silver per tonne, and 6 metres of 1.6% copper, 2.2% zinc and 58.2 grams silver (including 1.7 metres of 4.4% copper, 0.5% zinc and 106 grams silver).
Results from the first hole in the second phase of drilling, centred on the strike projection of the Mala Noche vein (beneath the workings of the old San Roberto mine), suggest the vein extends over 2 km to a depth of at least 450 metres and that it is open in all directions. Hole 20 returned 6.8% copper, 4.8% zinc and 100.3 grams silver, including 2.6 metres of 1.9% copper, 2.7% zinc and 138.7 grams silver. The vein system now extends over 5.5 km along strike.
The ongoing drill program is expected to total 7,000 metres. One drill rig is testing the Mala Noche vein to a depth of 400 metres below surface (down to the 2150 level of the mine and east of hole 20). Another will drill five more holes to test the 1900 level (650 metres below surface), and two holes will test a large geophysical anomaly at a depth of 1,000 metres.
Geophysical work over the Mala Noche vein trend has outlined further drill targets.
The Cozamin project contains historical measured and indicated resources of 2.7 million tonnes grading 85 grams silver and 0.5 gram gold per tonne, plus 0.95% copper, 3.16% zinc and 0.88% lead. The inferred resource consists of 3.1 million tonnes grading 103 grams silver, 0.5 gram gold, 1.41% copper, 3.21% zinc and 0.85% lead.
“The first twenty holes resulted in an average of 6.6 metres grading 2.61% copper, 91.25 grams silver and 1.38% zinc,” says Pylot. “The next step is to de-water the mine and rehabilitate the old workings. By early December, we hope to be drilling from underground.”
Once underground workings are accessible, they will allow for deeper drilling. “From there, we will be able to bring the historical resource up to standards of National Instrument 43-101, as well as expand the resource from the recent drill program on the San Roberto sector and the stepout holes.”
The Cozamin mill had processed at the rate of 250,000 tonnes per day in 1997. Recommissioning the plant is expected to cost US$660,000. Expanding the mill to 1,200 tonnes would cost some US$1.4 million, whereas expanding to 2,000 tonnes would cost US$2.7 million, according to an independent review.
In other news, Capstone ended its joint venture with
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