Based on a thorough examination of geophysical data,
Many of the geophysical targets are in the same stratigraphic intervals that host past-producing massive sulphide zones. EuroZinc will carry out a ground-based electromagnetic survey on several of the gravity anomalies in March. Initial drill-testing of the high-priority anomalies is scheduled for the second quarter.
The Vancouver-based company is working on a final feasibility study aimed at reviving Aljustrel, beginning in late 2000. The revived operation would treat 1.5 million tonnes of zinc-rich ore annually. Capital costs are estimated to be the range of US$40-50 million, though this amount could be reduced by European grants.
The study is examining the possibility of mining high-grade zinc and copper zones in the Feitais and Moinho deposits.
The latest resource estimates, calculated by Steffan Robertson & Kirsten, are based on data from 342 diamond drill holes and 964 underground channel samples. The two deposits are now reported to host a total resource (in all categories) of 141.3 million tonnes grading 2.79% zinc, 0.97% lead and 0.51% copper, plus 35 grams silver and 0.6 gram gold per tonne, at a zero cutoff grade. Both remain open downdip and down-plunge.
The zinc zone boasts a resource (in all categories) totalling 60.1 million tonnes grading 4.41% zinc, 0.31% copper, 1.45% lead, 49.67 grams silver and 0.69 gram gold, based on a 3% zinc cutoff. At a 4.5% cutoff, the total falls to 20.26 million tonnes of 5.9% zinc, 0.26% copper, 1.89% lead, 65.08 grams silver and 0.76 gram gold.
The copper zone totals 9.7 million tonnes of 1.03% zinc, 2.07% copper, 0.32% lead, 15.33 grams silver and 0.37 gram gold at a 1.5% cutoff.
The final bankable feasibility study is expected to be completed in the first quarter. It will include an evaluation of various development proposals, including one for the copper zone, and results from metallurgical tests.
Late in 1999, the company noted that more than 1,000 tonnes had been treated at an on-site pilot plant. Zinc recoveries of 82-84% were obtained from a zinc concentrate containing 48-50% zinc. Lead recoveries of 58-60% were obtained with a lead concentrate grade of 49-51%, with silver recovery to the lead concentrate projected to be 36-38%. The feasibility study is expected to have more precise numbers.
Aljustrel operated for several years in the early 1990s, but low recoveries (about 40% for zinc) and inefficient mining methods, combined with low metal prices, forced its closure. The existing 3,500-tonne-per-day mill and related facilities have been kept in good condition. The assets acquired by EuroZinc also includes a deep-water port.
EuroZinc holds a 75% interest in the project, with the remainder held by a state-owned enterprise.
Be the first to comment on "EuroZinc outlines new targets at Aljustrel"