Although recent exploration by
The discoveries were made in the north Slave Craton region, also known as the Coronation district. The area lost some of its shine earlier this year after the market was disappointed by lower-than-expected macrodiamond results from a surface sample of the Artemisia pipe, discovered last fall on the Kim property. Ashton’s field team discovered the outcropping Artemisia while investigating the source of an indicator mineral train and diamond-bearing kimberlite float. A vertical hole into the centre of this occurrence returned 812 micros, and 86 macros were from 246 kg of drill core. (A macro is defined here as exceeding 0.5 mm in one dimension.) An additional 85.5 kg of material sampled from outcropping kimberlite and talus yielded 309 micros and 34 macros.
Last fall, a larger, 1,157-kg sample was collected from three separate sites within the 150-by-140-metre interpreted body. The sample was processed for commercial-size stones and yielded a disappointingly low 0.2 carat of diamonds greater than a bottom-size 0.8-mm cutoff, for an implied grade of just 0.17 carat per tonne. By comparison, the commercial grades of the six Ekati mine pipes in the Lac de Gras area of the Northwest Territories range from 0.3 to 3.5 carats per tonne and average 1 carat, whereas the four Diavik pipes, which will comprise Canada’s next diamond mine, range from a low of 3 carats to a high of 5.2 carats per tonne.
Earlier this year, Ashton returned to the Kim property and by April had completed the collection of an 11-tonne mini-bulk sample from seven core holes into Artemisia. The drilling indicates Artemisia has a vent-like shape and is much larger than originally thought, measuring 250 by 150 metres to cover 3 hectares. The pipe has been drilled to a depth of 225 metres. Analyst John Kaiser, publisher of the Bottom-Fishing Report, suggests Artemisia could contain a 15-to-25-million-tonne resource to a depth of 300 metres.
Meanwhile, Ashton discovered an outcropping kimberlite, called Thrift, while investigating a 100-metre-diameter magnetic anomaly 2.5 km southwest of Artemisia. Kimberlite in outcrop and float were found on opposite sides of a lake measuring 75 metres in diameter. Ashton took surface samples of the new discovery for microdiamond testing but has not drilled the find.
The Kim property is held under the Slave Regional joint venture, in which Ashton has a 90% interest and
However, the relationship between the two partners has soured. In late May, Pure Gold filed a lawsuit alleging breach of contract against Ashton and is seeking one or two extra percentage points on several properties held under the Slave Regional joint venture, including the Hydra, Perseus and Artemisia claims. In addition, Pure Gold claims the right to an interest in properties Ashton acquired in Nunavut and the Northwest Territories outside of the joint venture during the past three years. Those would include the Kikerk Lake project Ashton optioned from
Ashton says the lawsuit is “utterly without merit” and will vigorously defend itself against these claims.
This spring, Ashton intersected a new kimberlite body on the 52.5%-owned Kirkerk Lake property, 10 km east of the Artemisia pipe. The newly discovered body, known as Stellaria, is 700 metres east of the diamond-bearing Potentilla kimberlite and oriented along a 2-km-long linear geophysical feature. A portion of this feature sits directly up-ice from a kimberlite indicator mineral train hosting a “significant” G10 garnet population.
A vertical hole drilled into a 160-by-50-metre shaped anomaly intersected 39 metres of hypabyssal kimberlite between a depth of 55 and 94 metres before terminating in limestone at 129 metres of depth. Core samples of the discovery will be analyzed for microdiamonds at Ashton’s caustic fusion laboratory in North Vancouver.
A 5.5-tonne mini-bulk drill sample of the Potentilla kimberlite was completed in early May. Discovered last fall, Potentilla returned 230 micros and 22 macros from a 207.8-kg aggregate drill sample of two distinct kimberlite facies. The bulk-sample drilling indicates that the surface expression of Potentilla is smaller than expected at 110 by 50 metres.
Two additional targets on the Kikerk Lake property were tested without intersecting kimberlite. Kikerk Lake is held 52.5% by Ashton, 30% by
The exploration success that Ashton has enjoyed in the north Slave Craton, along with its discovery of six kimberlitic bodies in north-central Quebec, clearly demonstrates that the company is doing something right. According to Brooke Clements, Ashton’s vice-president of exploration, the key to its success in both of those areas has been heavy-mineral sampling. “We use a combination of heavy-mineral sampling and geophysics, and usually the heavy mineral-sampling comes first,” says Clements. Some of Ashton’s discoveries in the Coronation district were made even before the area was flown with geophysics.
“Our exploration success in those two districts has been [a result of] the old-fashioned way — you look at an area that for whatever reason you feel is prospective, and you plan a reasonable pattern or density of sampling,” says Clements. “If you get a sniff of indicator minerals, you go back and collect more samples at a higher density. That’s what we did, starting in 1997 at Coronation and 1996 in Quebec.”
Ashton’s crews discovered kimberlite float in both areas while in the field conducting ground investigations on anomalous indicator mineral areas.
“We’ve had some good exploration success,” Clements continues, while conceding that “we’re still a long way from going towards feasibility.”
The London-based
The Anuri kimberlite was discovered in July 2001 at the edge of a lake where a 15-km-long indicator mineral train ended. In total, 600 micros and 337 macros were recovered from 656 kg of kimberlite core. Sixty-one of the macros are larger than 0.5 mm in two dimensions, and nine of the stones exceed 0.1 mm in two dimensions. The largest diamond recovered weighed three-quarters of a carat.
Kennecott followed in September with the discovery of a second kimberlite body, immediately east of Anuri. Microdiamond analysis on 129.4 kg of core from Anuri East yielded 75 micros and 34 macros, including five diamonds greater than 0.5 mm in two dimensions and a single stone exceeding 1 mm square mesh. A third kimberlite, known as Qamutiik, was found 9 km northwest of the Anuri discoveries but proved to be barren of diamonds.
Kennecott is earning an initial 25% interest in the 1,400 sq. km of mineral claims that comprise Tahera’s Rockinghorse p
roject by spending $25 million before May 2008. At the end of 2001, Kennecott had spent $21.3 million on the joint-venture claims. In return for funding all costs up to a mine development decision, Kennecott can earn a 62.5% stake.
During a spring drilling campaign, Kennecott further tested the Anuri kimberlites with four holes and significantly expanded their tonnage potential. The kimberlite bodies, each of which is shaped like a champagne glass, are believed to coalesce in the upper region. The surface expression of Anuri is 225 by 150 metres whereas Anuri East measures 100 by 100 metres. The kimberlites have been tested to a depth of more than 200 metres.
A new batch of diamond results has been reported for the bottom half of the first hole drilled this spring, which crosscut the Anuri kimberlites from east to west. A 213.4-kg sample of primarily Anuri East yielded 112 micros and 35 macros. Tahera says results to date indicate that the larger Anuri kimberlite exhibits stronger diamond grade. In total, 999 micros and 504 macros have been recovered from 1,227 kg of drill samples taken from both pipes. Ninety diamonds were recovered on top of a 0.5-mm square mesh, and 13 exceed a 1-mm square mesh size.
Drill-testing
Kennecott unsuccessfully drill-tested 12 exploration targets this spring within a 20-km-radius of the Anuri kimberlites. A number of remaining priority targets will be tested during a summer program.
Sitting right in the heart of the Coronation Gulf district is
De Beers, on the other hand, has suggested to Alston that it was not prepared to proceed with the joint-venture agreement until the DTC agreement was completed. Under the terms of a preliminary agreement dated April 2000, the Canadian exploration division of De Beers can earn a 70% interest in the property by spending $10 million over six years and carrying Rhonda to production. De Beers discovered the multi-phase Knife kimberlite pipe in June 2000 and recovered 208 micros and nine macros from 397 kg of tested core. A year ago, De Beers went back in and collected a 9-tonne mini-bulk sample from six holes. Drilling has confirmed the pipe’s dimensions as being 390 by 230 metres.
De Beers delivered the micro and macro results of 9-tonne program to Rhonda on Nov. 19, 2001. On the advice of its lawyers, Rhonda has neither opened nor reviewed those results. By doing so, the lawyers caution, Rhonda would legitimize the joint venture to a certain extent and weaken the company’s position should the matter end up in the courts. Rhonda is currently waiting for a re-draft regarding the sales and marketing agreement from the DTC. “It has become quite frustrating,” says Alston.
Inulik
Rhonda also holds a 100% interest in the Inulik property, covering 325 sq. km of ground adjoining the Knife project. A reconnaissance till-sampling program, carried out last summer across the property, revealed two sites that returned kimberlite indicator mineral counts in the tens of thousands. The mineral grains consist mainly of ilmenite and eclogitic garnets, with a scattering of pyropes. The two sites were 1.4 km apart from each other and 11 km from the Knife pipe.
A follow-up program of prospecting, till sampling and ground geophysics will further investigate airborne anomalies, two or three questionable mineral trains, and the immediate area surrounding the two concentrated indicator mineral samples.
The staking frenzy that engulfed the Coronation district late last year attracted various seasoned diamond explorers, including Randy Turner’s
Diamondex was quick to strike a deal on a large block of ground adjoining the western perimeter of the Vic property, held by Ashton and Pure Gold. Results from previous reconnaissance till-sampling suggest the presence of kimberlite indicator minerals.
Diamondex can earn a 70% interest in Peregrine by spending $1 million on exploration before the end of 2004. Northern Empire will retain 30%. Diamondex recently completed an 8,324-line-km airborne geophysical survey over the property and will follow with a program of ground geophysics, prospecting, till sampling and geological mapping over some 24 selected magnetic targets.
Diamondex added to its holdings in the north Slave area by a staking a further 200 sq. km in two claim blocks, which together comprise the Heeqqu property, 40 km southwest of the Rockinghorse project. The property will be subjected to airborne geophysical surveys, followed by till sampling and ground geophysics, funded from a $600,000 budget.
Minority interest
The Northair Group’s Northern Empire and
Northern Empire also holds ground in partnership with Stornoway on the Melville Peninsula of Baffin Island. There, the pair can earn a collective 70% interest in the Aviat North and Aviat South properties by spending $2 million over four years. Northern Empire and Stornoway will have a right of first refusal to acquire an additional 20% once they have earned-in. The partners have since brought in
Stornoway has transformed itself into a diamond exploration vehicle, with exposure to more than 5,726 sq. km of holdings in the Coronation district. With Catherine McLeod-Seltzer at the helm, Stornoway has added Grenville Thomas, founder of
Stornoway will remain one of the more active juniors in the Coronation Gulf as the company acts as operator for almost all of the joint ventures in which it’s involved. The company has already completed 6,500 line km of helicopter-borne magnetic and electromagnetic surveys over the Sceptre and Tiara properties. The two properties together comprise 890 sq. km and adjoin Rhonda’s Inulik property, as well as ground held by Ashton and Pure Gold.
28 targets
Twenty-eight priority targets have been selected from the airborne surveys for ground follow-up. Stornoway can earn a 60% interest in the Sceptre and Tiara properties from International Samuel,
Meanwhile, fixed-wing aeromagnetic surveys have been flown over the Jubilee, Coronation North and South, Orb, Bear and Jewel properties, held under various option agreements with several juniors. Stornoway’s summer field program will target the higher-priority anomalies. An estimated 2,100 heavy mineral till samples will be collected this summer.
Also, Augusta Resource owns a large land package in the Coronation area, represented by varying interests in 6,475 sq. km
of properties. Ashton has done a deal with Augusta on six of its wholly owned properties, which total 3,250 sq. km. Working on behalf of Augusta, Ashton will conduct reconnaissance heavy-mineral sampling across the properties at Augusta’s expense. Based on the sampling results, Ashton can then elect to earn a 60% interest by spending $8.7 million on exploration over four years.
Other juniors active in the North Slave include
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