MINING IN CHILE — Niugini projects increase in San Cristobal

The San Cristobal mine of Niugini Mining in the Atacama Desert in northern Chile produced 49,000 oz. gold and 139,000 oz. silver last year, compared with 58,000 oz. gold and 177,000 oz. silver in 1992.

Niugini, which is 52.6% owned by Battle Mountain Gold (NYSE), is projecting output in 1994 of 80,000 oz. gold and 241,000 oz. silver.

Cash production costs (per equivalent ounce) in 1993 averaged US$351 per oz., up from US$276 the previous year. Total operating costs (per equivalent ounce) also increased, to US$436 per oz. from US$358 in 1992. Proven and probable reserves (as of the end of 1993) at San Cristobal stood at 22.5 million tons grading 0.28 oz. gold per ton, up from 18.6 million tons averaging 0.27 oz. at year-end 1992.

The mine operates in an extremely dry environment; years may pass without rainfall. Because of the dry condition, Niugini has instituted a dust mitigation program designed to minimize airborne dust.

Battle Mountain, in its latest annual report, states that water is brought from Niugini-drilled wells about 24 miles away. Most of the water used in the treatment process is recovered and reused; some of the water is lost through absorption by the rock from which the gold is leached, and to evaporation. Test holes drilled to 1,000 ft. near the mine did not encounter a water table. Still, to minimize the environmental risk, Niugini has placed impervious plastic liners under the leach pads and is capturing the pregnant solution in a fully contained system, Battle Mountains reports.