Iamgold, Anglo bring Niamboulama to feasibility

Having completed their due-diligence review, equal partners Iamgold (IMG-T) and Anglo American are proceeding with a feasibility study of the Niamboulama gold deposit on the Yatela concession in western Mali.

The two companies recently acquired the Yatela concession from Australian-based Eltin for US$7.5 million in cash. Niamboulama occupies the southern end of the concession, and is 25 km north by road from the partners’ Sadiola gold mine, where production is expected to top 496,000 oz.

in 1998, at a total cash cost of US$133 per oz.

While the upcoming study will primarily focus on the Niamboulama deposit, the feasibility of incorporating its southern extension, the Kourketo West deposit, will also be examined. The latter deposit is situated at the northern end of the partners’ equally owned Sadex concession.

Resources for the Niamboulama deposit are pegged at 7.9 million tonnes grading 2.9 grams gold per tonne, whereas those for the Kourketo West deposit stand at 2 million tonnes grading 2.9 grams gold. Together, the deposits cover 900 metres of strike length and extend to a depth of 200 metres, where both deposits remain open. Both calculations are based on a cutoff grade of 1 gram. Resources for the Niamboulama deposit are based on results from drilling completed by Eltin.

Gold mineralization at Niamboulama occurs in free form and is hosted by a westerly-dipping regolith unit that is friable, oxidized and iron-bearing.

The unit is underlain by saprolitic Birimian rocks and overlain by younger unconsolidated sandstones.

Starting in April, Anglo will begin drilling 200 core holes totalling 21,000 metres. Several holes will test for a northern extension to Niamboulama, as previous drilling by Eltin suggests the possibility of mineralization extending another 1.1 km in that direction. The drilling will add to the 22 diamond drill and 52 reverse-circulation holes previously drilled by Eltin on the Yatela concession and the 14 twin holes completed by the partners during their due-diligence review.

Engineering and metallurgical studies will also be carried out as part of the feasibility study. An earlier study of the latter type by Eltin indicated that gold recovery rates in excess of 96% for oxidized material and 86% for partially weathered material are possible. For engineering purposes, the cost of constructing a milling operation on site will be compared with the costs of transporting material to the Sadiola facilities by pipeline, conveyor or truck. The feasibility of heap leaching will be compared with that of conventional plant treatment.

There is also potential to exploit a third deposit, dubbed Alamoutala, which lies between Kourketo West and the Sadiola mine. The deposit, which is on the Sadex concession, hosts 2.5 million tonnes of oxide resources grading 2.3 grams gold per tonne.

The study is expected to cost around US$8.5 million and should be finished by mid-1999. Anglo will cover all costs incurred on the Sadex concession and half of those incurred on the Yatela property.