A 7.4-tonne sample, processed for larger-size diamonds greater than 0.85 mm, delivered 6.52 carats for an implied sample grade of 0.88 carat per tonne. The largest stone recovered is a white transparent aggregate weighing 0.4 carat. Overall, the diamond population, consisting of predominantly dodecahedral and octahedral crystal forms, is dominated by white transparent stones with lesser amounts of brown coloured diamonds.
The outcropping AV-1 is exposed over an area measuring 76 by 13 metres at the edge of a small lake. The exposed portion consists of hypabyssal kimberlite. Last fall, the AV-1 exposure was stripped of overburden, washed and sub-divided into a grid series of 1-metre-square panels from which equal amounts of kimberlite were sampled using jackhammers. In total, 7.4 tonnes were collected and shipped to SGS Lakefield Research for processing by dense media separation.
Some 1,136 kg of kimberlite were originally retrieved from the AV-1 outcrop by surficial grab sampling in August 2002 and March 2003. In total, 1,613 microdiamonds were recovered by caustic fusion analysis, giving a microdiamond count of 1.42 stones per kg. Based on the microdiamond results, the diamond distribution curve for AV-1 suggests good potential for large, commercial-size stones. The accompanying table provides a detailed look at the microdiamond distribution.
The AV-1 showing was tested last summer with seven angle holes drilled from four setups. Based on the drilling, the multi-phase kimberlite body is believed to be at least 160 metres long and 40-60 metres wide. It remains open to the east and at depth.
Hypabyssal kimberlite was intercepted in all holes except one and shows good correlation with the double-lobed magnetic high anomaly identified from ground geophysics. A second, non-magnetic, brecciated macrocrystic kimberlite phase was encountered in five of the holes.
Caustic fusion analysis on 531.7 kg of core samples recovered 737 microdiamonds. The three largest stones measure 4 by 3.5 by 1.8 mm, 2.34 by 2 by 1.76 mm, and 2.4 by 1.48 by 1 mm. All were recovered from the breccia phase. The hypabyssal and breccia phases of AV-1 have returned comparable microdiamond counts of 1.44 diamonds per kg and 1.32 diamonds per kg, respectively, though the breccia appears to have a better coarse diamond distribution potential.
One of the objectives of this year’s program is to collect a mini-bulk drill sample of about 4 tonnes of breccia-phase kimberlite from AV-1 to test for larger diamonds.
AV-1 is one of two confirmed kimberlite bodies known to exist on the Aviat project in eastern Nunavut. A second outcropping kimberlite body, AV-2, was found during the summer of 2003, about 4 km east-southeast of AV-1. The dyke-like body was tested by a single inclined hole that intersected 2.6 metres of kimberlite beneath the surface exposure, followed by two other separate kimberlite sections of 9.3 metres and 3.1 metres. A second hole tested a magnetic anomaly 75 metres southwest of the AV-2 showing and encountered 2.2-metre-long and 6.5-metre-long sections of kimberlite.
“We initially thought AV-2 was simply a dyke, but drilling identified multiple kimberlite intercepts, suggesting that it is more complex in nature,” says Stornoway President Eira Thomas.
A combined, 39.4-kg drill sample of AV-2, including both hypabyssal and breccia phases, delivered 30 microdiamonds. The largest stone was a lone diamond caught on a +0.6-mm square mesh screen. In addition, a 48.6-kg sample collected from a surface exposure of AV-2 hypabyssal kimberlite held 34 diamonds, including a stone measuring 1.78 by 1.32 by 0.86 mm that was caught in the 1.18-mm-size sieve.
Significant quantity
“We have determined AV-2 contains diamonds in a significant quantity from such a small sample, and once again we have recovered some nice larger stones,” Thomas told delegates at the recent convention of the Prospectors & Developers Association of Canada, held in Toronto. “We will be going back to do more work.”
The Aviat project is a joint venture covering 5.5 million acres (22,260 sq. km) at the northern end of Melville Peninsula in eastern Nunavut. Stornoway owns a 70% interest,
Field crews at Aviat are preparing to drill-test up to six targets under lakes in the immediate vicinity of AV-1 before spring break-up. Complete indicator mineral data from the 2003 program, which saw roughly 2,400 till samples taken across the project area, are not yet available, but results to date show that AV-1 lies within a 3-km-wide distribution train. Till samples containing anomalous pyrope, eclogite and ilmenite grain populations have been recovered up to 2 km up-ice of AV-1. Strongly anomalous regional till samples, with more than 50 indicator mineral grains per sample and/or lithic kimberlite fragments, are well outside the prominent mineral train hosting AV-1, suggesting the potential for other kimberlite sources on the Aviat landholdings.
“Although final results from the 2003 sampling campaign are still weeks away, we have already identified several geochemical target areas that we expect will lead to new kimberlite discoveries in 2004,” stated Thomas.
Ground investigation of priority geophysical targets and prospecting of anomalous kimberlite indicator mineral trains will precede a larger drilling campaign, which is scheduled later in July or August. Last year, airborne geophysical surveys were flown over about a third of the northern block, and some “very nice” targets have emerged from those data.
Opportunity
“We feel the real opportunity is to find and discover an entirely new kimberlite cluster, which we will control,” said Thomas.
Stornoway is focused exclusively on diamond exploration in northern Canada. The junior holds varying interests in 20 million acres (80,940 sq. km) throughout the Melville Peninsula, Coronation Bay and Rankin Inlet areas of Nunavut. “We feel that this area is under-explored relative to the other diamond-producing regions around the world,” Thomas said. “We have gone about putting together a large prospective land package based on its high-potential geology. In addition, we have put together an experienced technical team that cut its teeth in the Lac de Gras area back in the 1990s and was directly involved in the discoveries at Diavik.”
A 2004 budget of $18 million has been approved for aggressive diamond exploration on the eastern Arctic properties held by Stornoway, including $9.5 million earmarked for the Churchill projects, near the community of Rankin Inlet, where an airborne geophysical survey is underway. The survey entails collecting more than 33,000 line km of magnetic and electromagnetic data from the core mineral claims, which cover the most favourable indicator mineral chemistry and the 18 kimberlite pipes discovered in 2003. The survey, which will be flown in two stages, is being conducted by Fugro Airborne Surveys using its helicopter-borne Resolve system.
Last summer,
First step
“This is a phenomenal first step,” says Thomas. “Back in the Lac de Gras area in the early 1990s at Diavik, we drilled 24 kimberlites before we found one that had interesting diamond counts, so we certainly view this as a positive development. Our challenge now is to find the source of those high-interest pyrope grains we identified in 2002. Our goal is to make sure the next kimberlite we find has higher diamond potential.”
In 2003, the joint venture improved the sample density by collecting more than 1,800 heavy mineral samples. The results will be used to direct the 2004 program. In February, Shear, Stornoway and BHP acquired a further 6.4 million acres (25,900 sq. km) surrounding and adjoining the Churchill project. The joint venture’s landholdings now encompass 8.4 million acres (34,000 sq. km) and are held 51% by Shear, 35% by Stornoway and 14% by BHP Billiton. International Samuel can earn up to a 65% interest in the adjoining half-million-acre (2,080-sq.-km) Churchill West project by spending $1 million on exploration, of which $565,000 has been spent.
Stornoway has a large exposure in the Coronation area through varying interests in 13 separate properties totalling 1.5 million acres (6,070 sq. km). After two years of work, several of the properties are at the drill ready-stage. In 2003, more than 2,600 till samples were collected from throughout the landholdings. Approximately $2 million will be spent this year on the Coronation properties.
Stornoway is adding to its $21-million treasury with a bought-deal private-placement financing that will bring in an extra $20 million. A syndicate of underwriters led by Raymond James has agreed to buy 8 million units of Stornoway at $2.50 apiece. Each unit will comprise one share and half a warrant. A whole warrant will allow for the purchase of an additional share at $3 for 12 months. The company has 59.7 million shares outstanding.
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