Drilling at the Bisha project in Eritrea has led to the discovery of a new massive sulphide zone, reports
The so-called NW zone was intersected in six holes collared on three sections. Another six holes failed to intersect the zone, which likely reflects local displacement of the sulphide body by felsic dykes.
Discovery hole B-56 intersected two intervals of sulphide mineralization some 30 metres and 39 metres in core-length. The first began 63.6 metres down-hole and averaged 0.74% copper and 0.01% lead, plus 6.6 grams silver and 0.07 gram gold per tonne; starting at 113 metres, the second ran 0.52% copper, 0.01% lead, 0.19% zinc, 4.5 grams silver and 0.21 gram gold.
The longest mineralized interval, intersected in hole 75, measured 46 metres (from 61 metres) and averaged 0.78% copper, 0.01% each of lead and zinc, 5.4 grams silver and 0.13 gram gold. It occurs in a zone of supergene enrichment and is immediately followed by 15.5 metres of stringer sulphides averaging 0.58% copper, 0.03% each of lead and zinc, 0.26 gram silver, 0.1 gram gold, and 16.5 metres of barren rock. Stringer sulphides occurred after that, with 4.5 metres running 0.01% each of copper and lead, 0.05% zinc, 12.7 grams silver and 6.74 grams gold.
The richest copper grades came from hole 66, which averaged 6.07% of the red metal, 0.02% each of lead and zinc, 38.9 grams silver and 0.85 gram gold over 3.1 metres (at 88 metres) of mixed supergene-enriched and stringer-type sulphides. The following 67.7 metres of core carried as much as 1.04% copper, 0.01% zinc, 28.2 grams silver and 6.01 grams gold over 6.1 metres.
In addition to the sulphides, 18 metres of mineralized oxides were intersected in hole 70. The section averaged 74 grams silver, 0.95 gram gold, 0.04% copper, and 0.03% each of lead and zinc.
Subsequent drilling, results for which are pending, have defined the northeasterly trending zone for 200 metres along strike. Mineralization remains open to the south and north.
The supergene horizon at the NW zone sits at a deeper level than at the Main zone. Also, in places the underlying sulphides are richer in gold
Downhole electromagnetic surveying is under way, following which drilling will resume.
Meanwhile, seven stepout holes at the Main zone have extended its strike length by 200 metres to the south, putting its overall length at 1.1 km. Subsequent drilling, for which results are pending, delineated another 50 metres of mineralization and extended the zone deeper, intersecting mineralization as deep as 200 metres below the surface.
Reported copper values varied from 0.05% to 10.29%; lead, from 0.02% to 0.84%; zinc, 0.01% to 18.68%; silver, 6 to 72.5 grams per tonne; and gold, 0.12 to 12.69 grams per tonne. The mineralized intervals varied from 5.3 to 36 metres.
Highlights include the following:
— hole 65 — 26.2 metres (at 52 metres) of supergene-enriched material grading 10.29% copper, 0.37% lead, 0.25% zinc, 72.5 grams silver and 0.88 gram gold, followed by 5.3 metres of mixed supergene and stringer sulphides running 1.56% copper, 0.01% lead, 0.05% zinc, 6 grams silver and 0.08 gram gold;
— hole 63 — 8 metres (at 60.5 metres) of supergene-enriched material running 4.74% copper, 0.3% lead, 0.8% zinc, 30.2 grams silver and 0.32 gram gold, followed by 36 metres of primary mineralization averaging 1.18% copper, 0.42% lead, 6.25% zinc, 43.3 grams silver and 0.92 gram gold;
— hole 61 — 36 metres (at 64 metres) of supergene-enriched material grading 1.05% copper, 0.02% lead, 0.01% zinc, 8.3 grams silver and 0.38 gram gold. The interval was preceded by 18 metres of oxides grading 71.5 grams silver and 12.69 grams gold, plus 0.07% copper, 0.05% lead and 0.06% zinc;
— hole 71 — 22.5 metres of sulphides (at 143.5 metres) grading 1.13% copper, 0.47% lead, 11.96% zinc, 71.3 grams silver and 0.64 gram gold, followed by 15.3 metres grading 3.03% copper, 0.01% lead, 0.89% zinc, 66.5 grams silver and 1.23 grams gold.
Two holes, 58 and 64, failed to return any significant results, and hole 59 was lost at a shallow depth, owing to technical difficulties with the rig.
Recent drilling targeted the primary zone of mineralization, given that the alluvial cover thickens towards the south, thus making geophysical methods the best method for spotting holes. Nevertheless, the overlying supergene and oxide horizons will be tested.
Nevsun plans to release an independent resource estimate in March. The delay follows the advice of consultant Snowden Mining Industry Consultants, which suggested more infill holes be added to the database.
In the current campaign, 133 holes comprising 11,000 metres have been completed. A total of 14,000 metres will be drilled in all.
In 2004, Nevsun plans to drill 34,000 metres using core and reverse-circulation rigs. An RC rig is to arrive on the property in January.
Earlier this month, Nevsun raised $47.6 million (gross) by privately placing 7 million units priced at $6.80 apiece. A unit consists of a share and half a warrant, with each full warrant entitling the holder to buy another share for $10 within five years. The shares will be subject to a 4-month hold period.
The units were placed with a syndicate of underwriters co-led by Salman Partners, Dundee Securities and Haywood Securities, and including BMO Nesbitt Burns, Canaccord Capital, and Westwind Partners.
The underwriters have an option to buy up to 3 million more units at the same issue price, up to 48 hours prior to the closing on Dec. 18.
Proceeds will be used to develop the Tabakoto and Segala gold projects in Mali and to explore Bisha.
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