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The Torngat property consist of four contiguous mineral exploration permits covering 444 sq. km on the eastern shore of Ungava Bay. Kangiqsualujjuaq (formerly known as George River) lies about 90 km southwest of the property, and the town of Kuujjuaq (formerly Fort Chino) is 250 km to the southwest. The property is accessible by boat, fixed-wing aircraft or helicopter.
In the centre of the property is a plateau, about 400 metres above sea level. The plateau is broken by steep-sided gorges and fjords, the largest of which is the Alluviaq Fjord.
The property is above the tree line and characterized by an Arctic climate. The predominant rock type is Tasiuyak, a northwest-trending belt of garnet-quartz-plagioclase gneisses that extend south to Labrador. The gneisses are considered to be altered sedimentary rocks.
In the southwestern part of the property, quartzo-felspathic gneisses of the Rae Province are exposed, whereas the northeastern portion is underlain by granulitic gneiss of the Burwell Terrane.
A number of kimberlite dykes crosscut the gneiss. The first dykes discovered are exposed in the steep walls on the northern side of Alluviaq Fjord. These dykes strike northeast, dip sub-vertically and weather preferentially, unlike the surrounding country rock.
The diamond-bearing kimberlite dykes were first recognized by government and university researchers in the early 1990s. Fjordland Minerals optioned a large land position in the Alluviaq Fjord area and conducted limited reconnaissance till sampling in August 1997, before walking away.
Twin Mining put together the Torngat land package between July and November 1999, while carrying out sampling on three kimberlite dykes: Torngat 1, 2 and 3. The largest of the dykes, Torngat 1, has an average width of 2.5 metres and was intermittently traced across the plateau for 1.5 km.
Several grab samples from various sites were analyzed by Lakefield Research for microdiamonds. An initial, 212.19 kg sample of material from the Torngat 1 dyke yielded 99 micros and 13 macros, with the largest diamond measuring 1.65 mm. (A macrodiamond is defined as exceeding 0.5 mm in at least one dimension.)
At the base of the cliff, Twin Mining sampled kimberlite rubble lying below the exposed Torngat dykes 2 and 3. A total of 37.8 kg of sample returned 42 micros and nine macros.
Torngat 2 measured 0.6 metre in width; Torngat 3, 1 metre. The two dykes are closely spaced, separated by 3 metres of gneissic country rock. The Torngat 2-3 dykes are about 700 metres north of Torngat 1.
The kimberlite dykes are described as dark green and generally coarse-grained.
A chill-margin of fine-grained kimberlite 10-15 cm thick occurs in Torngat 1, along contacts with the country rock. Further sampling has shown that the fine-grained margin has a lower diamond content. The fine-grained kimberlite is also more resilient to weathering.
Grab samples of the fine-grained kimberlite margins, weighing a total of 543.26 kg, yielded just 35 micros and six macros, whereas 140.05 kg of sample material collected across the coarse-grained core of the dyke returned 218 micros and 55 macros. Ten of the macros exceeded 1 mm in one dimension, the largest being 1.85 mm.
The dykes consist of olivine and phlogopite, contained in a matrix of fine-grained phlogopite, olivine, spinel, perovskite and carbonate. Geochemical work shows that the dykes are ultra-potassic and contain low silica and alumina, with high titania.
During the 1999 field season, a new set of kimberlite dykes was identified in an area called Torngat South, 10 km along strike to the southwest, near the Baufremont River. A 27.48-kg sample of kimberlite float taken from a weathered depression yielded seven micros.
As 1999 drew to a close, Twin Mining launched an airborne high-resolution magnetic, gradiometric and very-low-frequency (VLF) geophysical survey over the property. The survey revealed an extensive dyke system, with as many 46 interpreted dyke-like features, in addition to 27 discrete anomalies. The principal Torngat 1 dyke was interpreted to be part of a 30-km-long continuous system. Both the Torngat 2 and 3 dykes produced magnetic anomalies parallel to Torngat 1.
In January 2000, the company closed a $2.2-million special warrant financing at 35 and 45 through a syndicate led by Dundee Securities and including National Bank Financial. This was followed in May by an $8.8-million financing of flow-through and common shares priced at 85 each; the shares were again sold through Dundee and National Bank. At Sept. 30, Twin had 66.1 million shares outstanding, or 77.3 million fully diluted, with $7.4 million in cash.
In late March, the company began extracting 10-tonne samples from five selected areas. The objective of the program was to establish macrodiamond distribution along the principal dyke system and confirm the possibility of larger diamonds. MPH Consulting was retained to audit the sample collection and transport process.
The sample sites chosen had little snow cover and were believed to represent a random sample of the dyke system. Individual samples were taken from Torngat 1 and Torngat 2-3 on the plateau, close to Alluviaq Fjord. The projected extension of Torngat 1 was sampled at 4.5 km inland along strike. Two other samples were collected from the Kakivuq dyke, 4.8 km along trend and southwest of the Alluviaq Fjord.
To date, results from only two of the mini-bulk samples have been reported. The first two samples from Torngat 1 were processed by Saskatchewan Research Council before Twin Mining reached an agreement with Lakefield Research to process the remaining samples.
An 8.7-tonne sample, taken from site AD2 on the plateau area, returned 77 stones greater than 0.85 mm. The parcel of diamonds weighed 1.33 carats, for a preliminary grade of 15.3 carats per 100 tonnes. The largest diamond recovered measured 3.8 by 3.6 by 3.2 mm. At this site, the dyke has a reported width of 2 metres.
An inland sample of 8.7 tonnes, collected on the projected Torngat 1 extension at site DU, yielded 99 diamonds weighing 1.37 carats, indicating a preliminary grade of 15.7 carats per 100 tonnes. The largest stone measured 3.1 by 2 by 1.1 mm. The dyke is 2 metres wide at this site.
The recovered diamonds are described as white and transparent.
MRDI Canada, which was in charge of overseeing the sample processing, notes that the 10-tonne samples were taken from relatively shallow excavations and that a significant amount of non-kimberlite was observed in the sample, possibly diluting the kimberlite.
This past summer, three additional mini-bulk samples of about 100 tonnes each were taken from site AD2, over a strike length of 56 metres and to a maximum depth of 7 metres. During the summer exploration program, the cumulative strike length of the Torngat dykes was extended to 50 km, and a visible macrodiamond was found in a grab sample taken some 5 km south of the most southerly 10-tonne sample site. Two new kimberlite dykes were discovered 2 and 8 km northwest of the principal system.
In addition, Twin Mining carried out a comprehensive sampling program that included 50-kg samples taken at roughly 400-metre intervals along 37 km of cumulative strike. Some 29 samples, ranging from 250 to 400 kg, were taken at specific sites. The company noted that the width of the dykes exceeded 1 metre at 58% of the sample sites and 2 metres at 20% of the sites. Several blowouts of 4 and 7 metres were identified along the main dyke system.
In October, the company staked an additional 63 sq. km in an area where exploration crews discovered two parallel kimberlite dykes, 30 km east of the Torngat property.
The discovery of such an extensive diamond-bearing kimberlite dyke system in the Torngat region has resulted in the staking of more than 1,500 sq. km in the immediate area by as many as 11 different companies and individuals.
Tandem holds a 40% back-in right on the 470-sq.-km property held by Diamond Discoveries International, a private U.S. company that is expected to go public shortly. Once Diamond Discoveries has spent $5 million on exploration, Tandem can acquire a 40% stake in the property by paying $2 million.
Other companies active in the area include
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