EXPLORATION — Samira drilling exceeds expectations

Stepout drilling at the advanced Samira gold project in Niger has extended the Main zone another 50 metres along strike.

Etruscan Resources (EET-T), which owns a 90% interest in the project, says each of two reverse-circulation holes intersected the favorable Samira Horizon in what is being interpreted as a down-faulted block. Two previous holes, shallowly drilled, missed the unit and intersecting barren sedimentary and volcanic units, whereas a follow-up hole pierced a diabase dyke which, until now, was thought to mark the zone’s end.

“This dyke seems to split the horizon but appears to be shallower than we originally thought and is perhaps post-mineralization,” says Anthony Hayes, Etruscan’s vice-president of corporate development.

Hole RC-18, collared on section 2575, intersected 6.1 metres (63.6-69.7 metres) averaging 2.95 grams gold per tonne and 22.9 metres (83.4-106.3 metres) averaging 2.76 grams. Stepping out 25 metres to the west, hole RC 182 returned 47.3 metres (49.8-97.1 metres) of 3.53 grams gold, including 4.6 metres grading 17.57 grams. That hole ended in mineralization, suggesting a possible continuation at depth.

Hole 183 was abandoned in the diabase at 59.4 metres and was collared on section 2625. Nevertheless, several follow-up holes have since shown the horizon to continue 125 metres westwards, though assay results are still pending.

The new results are reportedly adding weight to joint-venture discussions between Etruscan and South African mining house Anglo American, which holds ground to the west, on which the Samira Horizon continues. (The horizon also continues eastwards, on ground held by Barrick Gold.)

“We are the central piece of the puzzle for Anglo,” says Hayes. “They’re very interested in it because of the area play, and the faulting would indicate that you don’t just have to look at shallow results; in some cases, you must go deeper.”

Hayes says Anglo plans to test the horizon across both properties using a proprietary electromagnetic technique that can penetrate 325 metres below surface in search of additional down-thrust zones.

Meanwhile, Etruscan has received results from 41 of the 71 infill holes drilled as part of a feasibility study on the oxide portion of the Main zone. Resources are pegged at 6.4 million tonnes averaging 2.49 grams gold, based on a cutoff grade of 1 gram.

Gold values varied from 0.49 to 7.04 grams per tonne over intervals ranging from 3.1 to 79 metres. Among the most impressive holes were:

• hole SA-114, collared on section 2300, which hit 48.1 metres (82-130.1 metres) averaging 2.49 grams gold, including 13.3 metres of 6.51 grams;
• hole SA-107, collared on section 2425, which hit 46.2 metres (20.8-67 metres) averaging 3.49 grams gold, including 19 metres of 6.49 grams;
• hole SA-104, collared on section 2475, which hit 79 metres (31.5-110.5 metres) averaging 2.36 grams, of which the last 20.5 metres graded 4.35 grams; and
• hole RC-172, collared on section 2500, which hit 52.8 metres (0-52.8 metres) averaging 3.57 grams, of which the last 38.1 metres graded 4.33 grams.

As well, a hole drilled at the eastern end of the zone, on section 2250, intersected 4 metres of footwall rocks that graded 0.44 gram gold. Another hole, sunk vertically in the zone’s centre, averaged 2.59 grams over 101.7 metres. Both intervals start at surface, and the second one contains two sub-intervals of 13.7 and 19.8 metres grading 4.47 and 3.96 grams, respectively.

Results are pending for the remaining holes, and drilling continues to search for more extensions. Once this work is complete, the company will attempt to elevate the resource to the measured category.

Etruscan believes the oxide resource can support a 3,300-tonne-per-day, open-pit, heap-leach operation capable of producing 70,000-80,000 oz. gold per year. Cash costs are expected to average US$150 per oz. over a mine life of eight years, with startup costs pegged at US$12 million.

The study is being managed by Mineral Resources Development Inc. (MRDI), with assistance from several firms that are focusing on metallurgical, design and environmental aspects. Metallurgical tests, which will include core from the recent vertical hole, and cost analyses are scheduled for completion in the coming weeks. The entire study is targeted for completion in the first quarter of 1999, and it is anticipated that production will follow in the fourth quarter.

Gold mineralization in the Samira Horizon is structurally controlled and occurs as disseminations in sedimentary rocks sandwiched between greenstones. Mineralization is oxidized and altered to saprolite to a depth exceeding 100 metres, below which it occurs in fresh rock in association with sulphide minerals, predominantly in the form of pyrite and arsenopyrite.

In total, the Samira deposit hosts indicated and inferred resources of 27.8 million tonnes averaging 2.02 grams gold, spread over 800 metres of strike length and to a depth of 200 metres. The Main zone accounts for 300 metres of that strike length and has been intersected 50 metres deeper.

Samira was discovered in the early 1990s during a government-sponsored program of regional mapping and prospecting. Etruscan acquired the property in 1996 and proceeded to enlist the help of Placer Dome (PDG-T), which, until its departure earlier this summer, managed and operated the exploration work.

Since then, Etruscan has been discussing a deal with Anglo. Such an agreement could include all the company’s West African properties.

Samira is on the 620-sq.-km Tiawa property. The remaining 10% interest in the property is held by the state on a carried basis.