MINING IN AFRICA — Hemlo Gold sets its sights on West Africa

The Hemlo gold mines of Ontario may well be the richest in Canada, but, as the companies that operate them are well aware, their productive lives will eventually come to an end. And that, in a nutshell, explains why Hemlo Gold Mines (TSE) has cast its eye on the gold potential of West Africa.

In June 1995, the Toronto-based gold producer spread its wings beyond its mine in Hemlo, Ont., toward the emerging gold camps of West Africa.

Under a joint-venture agreement with Montreal-based Birim Goldfields (CDN), Hemlo Gold can earn a 65% interest in the Dunkwa property in Ghana by spending $7 million over four years.

The work programs operated by Birim have given Hemlo Gold cause to be optimistic about the property’s potential.

Early this year, for example, the two companies announced assay results from three diamond drill holes on the Mampon discovery, one of several targets on the Dunkwa property.

The first hole returned an average of 6.4 grams gold per tonne (6.2 grams cut) from 0 to 61 metres (0.21 oz. gold per ton over 200 ft.), including an interval of 28 metres grading 11.07 grams.

Birim notes that the results from the first diamond drill show good overall correlation with the previously reported, reverse-circulation assays.

In November 1995, Birim announced results of a reverse-circulation drill program which showed continuous gold mineralization in bedrock, averaging 6.3 grams over 45 metres of true width. Included in this section were two central holes which bottomed in high-grade mineralization: 15.8 grams over 13 metres and 14.8 grams over 8 metres. One of the holes, No. 14, averaged 7.07 grams over its entire length of 59 metres.

Birim President Denis Simoneau says the diamond drilling is being carried out so that results can be compared with those achieved in the

reverse-circulation program. “Everyone is a little nervous about reverse-circulation because some companies have had problems with it in the past,” he tells The Northern Miner. “That is why we are pleased with the results to date from our diamond drilling.”

The second diamond drill hole intersected 123 metres of 2.96 grams from 0 to 123 metres, which includes 14.3 metres of 11.06 grams. (This hole duplicated previously reported reverse-circulation hole 16.)

The third diamond drill hole was a stepout hole, drilled to test the possible continuation of the structure to the south. It returned 12.6 metres of 0.62 gram and a 27.2-metre interval of 0.81 gram.

Birim notes that these holes showed quartz and carbonate alteration, as well as pyrite and arsenopyrite, which are indicator minerals for gold mineralization on the Ashanti gold belt.

In light of these results, the joint venture has ordered a second diamond drill for the Mampon discovery. Regional and detailed soil geochemistry surveys are in progress, along with geological mapping and sampling of other known prospects.

Birim says drilling to date has confirmed the extension of the mineralized zone to a vertical depth of about 110 metres below surface. The oxide-sulphide transition occurs at a vertical depth of about 30 metres below surface.

Birim’s Dunkwa prospecting licences cover a contiguous area of about 230 sq. km along the Ashanti gold belt. The property straddles a 45-km strike zone of highly favorable geological formations and structures identical with those hosting the Ashanti Goldfields mine to the north, and Gencor’s Bogusu mine to the south.

The property is underlain by metasedimentary volcanic lithologies. Mapping has identified four different lithologies within the Birimian Supergroups. >From stratigraphic top to base, these are as follows: metapelites, basic volcanics, graphitic phyllites and turbidites.

In the late 1980s, BHP Minerals carried out some exploration on the property and identified targets for future exploration. Preliminary resources have been identified at several prospects on the Dunkwa property, including Mampon, which hosts oxide mineralization estimated at 885,000 tonnes averaging 1.37 grams gold per tonne. BHP relinquished the property because deposits exceeding 1 million oz. were not found in the initial stages of exploration. Nevertheless, Birim views all the results achieved so far at Dunkwa as promising and believes potential still exists for the discovery of major reserves.

Today, Dunkwa is viewed as prospective for heap-leachable, gold oxide reserves, as well as higher-grade reserves that would require underground mining techniques.