Westmin, Atna concerned over selenium at Wolverine

High selenium content could hinder the economic potential of the Wolverine volcanogenic massive sulphide deposit in the southeastern Yukon.

Partners Westmin Resources (WMI-T) and Atna Resources (ATN-T), which own 60% and 40% interests, respectively, report that metallurgical tests identified high levels of selenium in the crystal structure of all of the major sulphide minerals in the deposit and in the copper, zinc and lead concentrates. Investigations by Westmin regarding the marketing of these concentrates indicate that the high levels of selenium may pose a problem, as they would be greater than those normally treated at copper and zinc refineries. Selenium is regarded as a contaminant in the refining process.

The presence of the metal limits the refinery’s ability to treat the concentrate and, consequently, drives up costs.

Harlan Meade, Westmin’s vice-president of exploration, says the high selenium levels are not restricted to the Wolverine deposit, and are a common problem in the Finlayson-Wolverine camp.

Cominco (CLT-T), which is advancing the ABM polymetallic deposit at its Kudz Ze Kayah project, 20 km to the west, has reported no metallurgical concerns.

Westmin and Atna recently concluded the 1997 exploration drilling program at the Wolverine project. The work was aimed at defining the high-grade deposit and exploring for additional deposits along the 20-km belt of favorable geology.

Of the 22 holes drilled this year, 19 intersected potentially ore-grade mineralization outside of the previously defined limits of the deposit, which were conservatively estimated at 5.3 million tonnes grading 12.95% zinc, 1.53% lead and 1.41% copper, plus 1.81 grams gold and 359.1 grams silver per tonne.

Drilling has pretty much defined the limits of the deposit along strike, though additional drilling will be required to delineate the eastern edge of the deposit.

Results for two final holes in the eastern extension of the deposit included: a true thickness of 0.27 metre grading 15.2% zinc, 7.86% lead and 0.73% copper, plus 5.32 grams gold and 1,974 grams silver, in hole 97-111; and a true width of 1.94 metres grading 2.49% zinc, 0.05% lead and 0.16% copper, plus 0.21 gram gold and 40 grams silver, in hole 97-112.

The deposit remains open downdip and likely continues on to ground held to the north by Cominco.

Atna President Peter DeLancey was quoted earlier this summer as saying the Wolverine deposit will likely be in the 6-to-7-million-tonne range. A new geological resource estimate will be released in November.

Exploration drilling identified narrow intervals of high-grade massive sulphide mineralization in the Sable zone, 1.6 km southeast of the Wolverine zone, adjacent to the boundary of the Puck claims.

Hole 97-106 intersected a previously reported 0.6-metre true width grading 15.7% zinc, 0.62% lead and 0.65% copper, plus 2.26 grams gold and 183 grams silver. Hole 97-108, a 65-metre stepout to the east, hit a previously reported true thickness of 0.6 metre grading 13.3% zinc, 0.79% lead and 0.8% copper, plus 1.92 gram gold and 416 grams silver.

Stepping out 100 metres downdip between the two holes, hole 97-110 intersected the target horizon but encountered no massive sulphide mineralization. The presence of significant footwall-type chlorite alteration with stockwork chalcopyrite and pyrrhotite veins indicates that a massive sulphide deposit may have formed nearby. However, no significant values were reported in stepout holes along strike in either direction.

The adjoining Puck claims are held under option from Expatriate Resources(EXR-V). The Westmin-Atna joint venture can earn a half interest by spending $2 million on exploration over two years.

Exploration drilling in the Fisher zone area, 8 km northwest of the Wolverine zone, continued to show lots of smoke. Hole 97-91 encountered intense alteration plus disseminated and stringer zinc mineralization in an area 2 km southeast of the Fisher zone.