Asarco drops Butte Highlands

Unsatisfactory drill results have prompted copper giant Asarco (NYSE) to drop its option on the Butte Highlands gold property in Montana.

The major had an option to acquire a 51% interest in the project from Orvana Minerals (TSE). It acquired the option in 1994 upon completing both infill and stepout drilling on the Nevin Hill deposit.

Orvana had estimated the Nevin Hill resource at more than 2 million tons grading between 0.3 and 0.6 oz. gold per ton. Gold mineralization occurs in multiple zones within a steeply dipping skarn measuring 200-300 ft. in thickness.

Asarco’s 1995 drilling program was designed to test a deep conceptual target downdip from the known mineralization. The target is described as a structurally controlled

deposit in the Meagher dolomite, which overlies the Wolsey shale (host of the Nevin Hill deposit).

Targeted to a depth of 2,000 ft., Asarco drilled five holes, but only two penetrated the Meagher into the Wolsey zone. One intersection in the Wolsey horizon returned 28.5 ft. grading 0.34 oz. gold.

In the previous year, Asarco carried out infill and stepout drilling on the Nevin Hill deposit itself, returning intersections ranging up to 13.5 ft. of 0.48 oz. gold in hole BH94-3.

Orvana plans to continue working the Butte Highlands project, with an emphasis on delineating the Nevin Hill zone further. It also intends to explore the strike extension of the Wolsey formation to the east.