In only three years,
By conducting an aggressive northern reconnaissance exploration initiative, the junior acquired nearly 5.2 million hectares of diamond prospective permits across the Far North earlier this year, second only to
Led by President Mark Kolebaba, formerly with
Teck Cominco is taking an aggressive approach at Victoria Island by committing $3 million this year to drill-test upwards of 75 to 100 kimberlite targets. Divided between Nunavut and the Northwest Territories, 700 km north of Yellowknife, Victoria Island was recognized for its diamond potential by Diamonds North’s predecessor, Major General Resources, in 1993. The premise that Victoria Island was underlain by an Archean basement was later supported by the age-dating of granitic rocks, which confirmed that the basement is a northern extension of the Slave Craton. De Beers originally discovered 16 kimberlite bodies at Victoria Island through the mid-to-late 1990s; all but one proved diamond-bearing. By the time De Beers pulled out entirely of the Victoria Island region in 2000, Major General had become the dominant landholder, and in the process acquired De Beers’ winterized camp and ownership of 29 isolated mineral claims, covering many of the original kimberlite discoveries. These claims are subject to a 1.5% gross over riding royalty payable to De Beers.
Major General completed a re-organization in early 2002, spinning off its diamond assets into the newly created Diamonds North. Major General was subsequently re-named
Today, Diamonds North holds more than 800,000 hectares of claims on Victoria Island, including the Blue Ice, Hadley Bay, White Ice, Yankee, Wellington, Argonaut, Holman and Washburn properties. The company has since discovered an additional 20 kimberlite bodies and showings, bringing the number of known kimberlite dykes, blows and pipes to 36.
More importantly, relatively small kimberlite samples from a number of the bodies, including King Eider, Sculptor, Vega and Snow Bunting, have demonstrated high microdiamond counts and a favourable distribution towards larger, commercial-size stones. A month ago, Diamonds North announced the recovery of a 3/4-carat diamond, measuring 5.5 by 4.2 by 3.1 mm, from a composite 679.2-kg sample (KE1) collected by Teck Cominco during drilling on King Eider in the 2004 field season. The samples were taken from four holes completed in the central portion of the pipe-like body.
The 0.74-carat stone is amongst a 1.32-carat parcel comprising 434 microdiamonds, 10 of which exceed a 0.85-mm square mesh sieve-size. (A detailed look at the diamond distribution is provided in the table on page 16.) The actual weight of those diamonds exceeding 0.85 mm is 1.09 carats, which equates to a sample grade of 1.6 carats per tonne.
A second composite sample (KE2) weighing 119.5 kg and consisting of distinctly different kimberlite material collected along the margins of King Eider, held only 17 microdiamonds no bigger than 0.212 mm in size. Of the 451 microdiamonds recovered in total, 90% of the stones are described as being transparent; of those, 70% are white in colour, 18% are grey and 11% are brown. A single pink transparent diamond was also recovered.
Defined by a distinct magnetic anomaly measuring 300 by 200 metres, the exact size of King Eider has not yet been determined, though Diamond North believes there is potential for somewhere between 2.5 and 5 million tonnes of kimberlite. The geophysical signature of this highly complex, multi-phase kimberlite consists of a magnetic high covering the eastern half of the body and a magnetic low over the western half.
King Eider was previously tested in 2002 by two angled scissor holes, which intersected multiple phases of kimberlite in more than 100 metres of core. The core was separated into five sub-samples, each representing a different kimberlite phase. In total, 389.9 kg of samples yielded 64 microdiamonds, whose size distribution suggested the potential for larger-size stones. The two largest stones, measuring 1.17 by 1.17 by 1.13 mm and 1.45 by 1.2 by 0.66 mm, were caught on the 0.85-mm screen. One of the better sub-samples, taken from 79-101 metres down-hole, held 25 microdiamonds in a 68-kg sample, including the second-largest stone.
Victoria Island
The Victoria Island kimberlites occur mainly as a series of en echelon dykes and blows, with a number of pipes, along four distinct structural or linear trends — Galaxy, King Eider, Apollo and Snowy Owl — all running northwest-southeast.
The Blue Ice holdings cover the Galaxy trend, a 20-km-long corridor that straddles the Northwest Territories-Nunavut border and hosts 14 kimberlite occurrences, such as Snow Goose, Gosling, Snow Bunting, Sculptor, Sand Piper and Vega. The corridor is defined by magnetic geophysical surveys and indicator mineral sampling.
“Microdiamond quality and colour include a high proportion of clear, white stones and some pink, yellow and brown diamonds,” reports Diamonds North. “Peridotitic and eclogitic minerals with diamond inclusion compositions are well represented in the Galaxy kimberlites, indicating the kimberlites have sampled two potential sources of diamond from the Earth’s mantle.”
A second parallel magnetic trend of kimberlite bodies and showings is centred on the King Eider pipe, 30 km to the north on the Hadley Bay project. The King Eider trend is more than 25 km long and hosts eight kimberlites, including Blizzard, Turnstone and Jaeger. Kimberlites along the King Eider corridor consistently yield fewer microdiamonds relative to Galaxy, however they show a strong presence of larger stones. A high proportion of the microdiamonds are transparent, white stones, with very few yellow- and brown-coloured. Mantle minerals have a strong eclogitic signature and exhibit diamond inclusion compositions.
Kolebaba says the potential of the King Eider corridor can be further illustrated by the Blizzard showing, which has yet to be drilled. Prospecting in 2003 resulted in the discovery of two narrow kimberlite showings set 1 km apart, 9 km southeast of the King Eider pipe. The exposures are described as disaggregated hypabyssal kimberlite, with apparent widths of up to 0.3 metre. The showings are part of a subtle airborne linear anomaly that extends more than 9 km in length. A 120-kg sample trenched from one of the showings produced 13 microdiamonds, including one sizeable stone measuring 2.22 by 2.17 by 1.26 mm that sat on the 1.7-mm mesh sieve. “In light of King Eider, we certainly want to go back to that now,” says Kolebaba.
The Apollo trend contains four kimberlite occurrences and is 25 km northeast of the King Eider corridor. The Snowy Owl trend, 40 km southeast of Galaxy, hosts seven diamond-bearing kimberlites.
Under a 2003 option agreement, Teck Cominco can earn up to a 70% interest in the Victoria Island Blue Ice project, which has been amended to include the Hadley Bay and White Ice properties. The White Ice claims were staked in early 2003 to cover the potential northwestern extensions of the Galaxy and King Eider lineaments, based on in
dicator mineral occurrences.
As the operator, Teck can earn an initial 30% stake by spending $11.5 million on exploration by the end of 2006. Teck can then elect to increase its interest to 50% by incurring an additional $5 million over one year. Should Teck continue funding all exploration costs to the completion of a feasibility study, the major would boost its stake to 65%. Teck can earn an additional 5% by project financing.
On Victoria Island, the Archean basement is overlain by a Proterozoic sedimentary sequence with minor volcanics, capped by flat-lying, 100- to 200-metre thick Cambrian-to-Devonian sediments. At least three mafic dyke sets intrude the granitic and Proterozoic sedimentary rocks. The Victoria Island kimberlite intrusions, which have been dated at 256-286 million years, occupy the same structural conduits as the mafic dykes and pierce the Paleozoic sediments. Supportive mineral chemistry including major oxides and trace element analyses suggests a cool geotherm, presence of potential peridotitic diamond sources and a strong diamond-bearing eclogitic signature.
The host cover rocks are largely non-magnetic, and the kimberlite bodies stand out as distinct “sharp” anomalies, compared with the more “rounded” anomalies caused by deep features in the basement or within the sedimentary rocks. Kimberlite intrusions are associated with both positive and negative magnetic signatures. Rare thin volcanic beds in the limestones, as well as concentrations of exotic magnetite, are the cause of some of the anomalies.
In 2004, Teck Cominco completed a two-phase exploration program on Victoria Island at a cost of $3.4 million. During the first phase, ground geophysical surveys were conducted over 60 targets. In addition, a test electromagnetic (EM) and magnetic survey covering almost 3,000 line-km was flown over parts of the Galaxy and King Eider trends. Diamonds North’s Kolebaba tells The Northern Miner that the standard Dighem EM previously flown at Victoria Island didn’t respond to the kimberlites at all. Instead, Diamonds North has been experimenting with the new Resolve system, which has outlined some promising circular EM anomalies, with associated subtle magnetics. The new EM system successfully defined Snow Goose and other known kimberlites.
Last year, drilling started late and ended early owing to poor weather conditions. Based on previous favourable microdiamond results, the Snow Bunting, King Eider and Turnstone kimberlites on the King Eider trend were targeted for further sampling. Results are pending for a 250-kg sample collected from the Turnstone kimberlite, which lies 5 km along trend of King Eider. A small 20-kg surface sample taken from the Turnstone showing in 2002 yielded three microdiamonds. Of significance, is a larger 1.03-by-0.71-by-0.64 mm stone that was caught on the +0.60-mm square mesh screen.
The Snow Bunting kimberlite is a steeply dipping kimberlite dyke structure, with an estimated true width of up to 8 metres. It is defined by a distinct magnetic anomaly measuring up to 200 metres in length. The kimberlite forms part of 2.7-km-long segment of semi-continuous kimberlite dykes and blows along the southeast end of the Galaxy trend. These include the Virgo, Sand Piper East, Sand Piper and Vega kimberlite prospects. De Beers originally recovered 23 diamonds from a 137-kg sample at Snow Bunting collected from a single reverse-circulation hole in 1997. Diamonds North re-tested Snow Bunting in 2002 with an angle hole; a 16.7-kg sample yielded 15 microdiamonds, four of which exceeded 0.5 mm in two dimensions.
Diamonds North returned in 2003 and collected a much larger sample from Snow Bunting by drilling downdip to a depth of more than 90 metres. Two distinct phases were identified and sampled separately: a dominant olivine macrocrystic hypabyssal kimberlite, labelled SB1, and a strongly serpentinized, clay-altered macrocrystic kimberlite, called SB2. A composite sample of SB1, weighing 163 kg, delivered 77 microdiamonds, including four stones exceeding 1 mm in two dimensions. The largest stone measured 1.34 by 1.14 by 1.2 mm. By comparison, a 54.6-kg sample of SB2 returned 11 microdiamonds, with only 1 stone greater than 0.5 mm in two dimensions.
The 2004 drill program at Snow Bunting was designed to further test the geometry and diamond potential to the east of the 2003 drilling. The two holes drilled in 2004 intersected two fine-grained hypabyssal kimberlite dykes, ranging from 0.6 to 5.3 metres estimated true width, with few indicator minerals. A combined sample, weighing 71.3 kg, held only five microdiamonds no bigger than a 0.3-mm sieve-size classification. Diamonds North believes they encountered a different phase of kimberlite in the 2004 holes.
The 2004 program also tested a new kimberlite dyke prospect, called H-1, found between the Meister and Jaeger kimberlite prospects along the central portion of the King Eider corridor. A 21.1-kg sample recovered from a 1.7-metre true width intercept of kimberlite returned only one microdiamond. Additional till sampling focused primarily on the 30-km stretch between the Galaxy and King Eider corridors.
This year, Teck has already gotten a head start and is using a reverse-circulation rig to test upwards of 75 high-risk geophysical targets. Should they hit on any one of these targets, a core rig will be used to further sample the kimberlite. The core rig will also be used to test as many as 30 targets of higher confidence. There will be some additional airborne EM conducted, and there has been talk of increasing this year’s exploration budget to incorporate a larger bulk-sample from the King Eider kimberlite.
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