Drilling tests copper-cobalt targets in Mexico

Drilling on Copperstone Resources’ (VSE) Purgatorio concession in Mexico has confirmed the continuity of sediment-hosted copper-cobalt mineralization.

The concession, situated north of Santa Rosalia in Baja California Sur, adjoins a portion of the eastern border of the Boleo copper-cobalt project under development by International Curator Resources (TSE).

Four drill holes — part of an ongoing, 3,000-metre program — intersected several mineralized beds which dip moderately to the north. The beds in fact become shallower to the southeast, showing potential for an open-pit resource. The No. 2 bed, encountered in holes 5 and 6, returned 1.6 metres of 0.11% copper plus 0.086% cobalt, and 2.85 metres of 0.094% copper plus 0.063% cobalt, respectively.

The No. 3a bed, which lies 50 metres below No. 2, returned 0.29 metres of 0.14% copper and 0.117% cobalt for hole 5; 0.68 metres of 0.06% copper and 0.144% cobalt for hole 6; 1.62 metres of 0.29% copper and 0.071% cobalt for hole 7; and 1.54 metres of 0.46% copper and 0.107% cobalt for hole 8. The No. 3 bed is separated from No. 3a by a further depth of 4 to 7 metres. Intersections include 2.8 metres of 0.25% copper and 0.049% cobalt for hole 5; 1.98 metres of 0.55% copper and 0.064% cobalt for hole 6; 2.59 metres of 0.23% copper and 0.053% cobalt for hole 7; and 1.27 metres of 2.71% copper and 0.103% cobalt for hole 8.

The No. 4 bed lies 70 to 84 metres below No. 3, and holes 6 and 8 returned intervals of 0.15% copper plus 0.119% cobalt over 1.1 metres, and 0.37% copper plus 0.043% cobalt over 5.05 metres, respectively.

So that the extent of the updip may be tested, a further hole is planned to the southeast.

Two additional holes were drilled on the Infierno concession, situated next to the northern portion of Curator’s Boleo project. One hole was lost to caving while the other intersected 0.49 metres of the No. 4 bed grading 0.33% copper and 0.108% cobalt.

Drilling is planned for Copperstone’s other nearby concessions, including San Luciano and Lucifer, as well as Yaqui and Belga. San Luciano is within the southern end of Curator’s holdings and contains geologic reserves estimated from 16 holes at 500,000 tons averaging 3.5% copper. Copperstone intends to re-drill to determine cobalt values and to upgrade reserves by testing the hangingwall of the ore bed.

Situated west of Infierno is the Lucifer concession, where several holes will test the continuity of the Boleo copper-cobalt beds. Prospecting in the past was hampered by an overlying younger sequence of volcanics.

The Yaqui and Belga concessions exist 24 km north up the coast, in a separate basin which hosts sediments similar in lithology and setting to the Boleo sequence. Four holes will test for copper mineralization.

Copperstone is earning an 80% interest in all six of the concessions from operator Island-Arc Resources (VSE).

Meanwhile, Curator released assay results of the remaining 21 holes of its fall drill program at the Boleo project. These last holes were drilled on grid spacings of 400 metres in the Saturno and Mercurio areas, along the western edge of the drill-indicated, open-pit resource. That resource is estimated at 91.5 million tonnes averaging 0.7% copper and 0.08% cobalt. The average stripping ratio of the No. 3 bed at Saturno is 4-to-1, while at Mercurio it is estimated at 10-to-1.

Drilling of the No. 3 bed in the Saturno area extended the zone 500 metres to the northwest, with four holes averaging 0.93% copper and 0.078% cobalt over 5.94 metres. Seven holes in the Mercurio area intersected the No. 3 bed, returning an average grade of 1.37% copper and 0.062% cobalt over 6.54 metres. Curator has focused its attention on the No. 3 bed because its greater widths bode well for strip mining. The No. 2 bed lies 40 to 50 metres above No. 3 and averages 0.4% copper, 0.06% cobalt and 1% zinc over a width of about 2 metres. The company believes that by mining No. 2 in conjunction with No. 3 in those areas where the No. 3 is deeper than 50 metres, the stripping costs can be reduced.

A revised reserve calculation is expected before the end of February, and upwards of 3,000 metres of additional drilling are planned for the next phase of work, which will continue to infill and expand the copper-cobalt mineralization.

Meanwhile, metallurgical testing is under way by Lakefield Research on 50 composite samples to determine the leaching characteristics of the copper-cobalt mineralization. Particular emphasis will be directed to the No. 3, so that the nature of the oxidation there may be better understood.