Although diamond exploration in Saskatchewan never attracted the amount of attention it did in Alberta, a handful of companies are determined to continue the search.
Saskatoon-based
Situated 60 km east of Prince Albert, the English Creek property consists of 15 contiguous claims totalling 46.1 sq. km. Shore owns a 100% interest in an additional 61 claims covering 169 sq. km in the immediate area.
The project area sits at the southern end of the northwesterly striking Fort la Corne kimberlite belt that extends over a 50-km distance and contains some 73 kimberlite bodies.
The kimberlites are in the form of stacked, sub-horizontal zones of crater facies that have been emplaced in a sequence of Cretaceous shales and sandstones. This sedimentary sequence is up to 170 metres thick and underlain by 450 metres of Cambro-Ordovician dolomitic carbonate rocks. The entire package lies unconformably over metamorphic basement rocks that are interpreted to be of Proterozoic age and to form part of the Glennie Domain of the Churchill province. The property is covered by 80-125 metres of unconsolidated glacial overburden.
In 1996, Shore encountered multiple kimberlite horizons while drill-testing three distinct higher magnetic portions of the much larger Star anomaly. An area measuring 1,500 by 600 metres was initially tested with three widely spaced holes. A uniform sequence of up to four separate horizons of kimberlite and kimberlitic sediments was intersected in each of the holes, starting at a depth of about 85 metres from surface. A visually distinct, higher-grade kimberlite unit near the top of the sequence ranged in thickness between 20 and 58 metres.
Caustic fusion analysis by the Saskatchewan Research Council yielded seven macros and 162 micros from a combined 383.6-kg sample of the upper unit collected from the three holes (a macro is defined as a stone exceeding 0.5 mm in at least one dimension). An additional 81.4 kg of material, primarily taken from hole 96-3, outside of the main zone, returned three macros and seven micros. The largest stone measured 1.5 mm.
Shore followed-up by drilling two larger-diameter PQ core holes (3.3-inch diameter) near the site of hole 96-3 in the fall of 1997. The larger-diameter core yielded a significantly higher diamond count over the smaller size core. Saskatchewan Research Council recovered a total of 67 macros and 682 micros from 982.6 kg of kimberlite sample. The upper main zone accounted for 65 of the macros and 637 of the micros in 817.8 kg of core. The largest diamond recovered measured 2 mm.
Eighty-nine per cent of the stones are described by Shore as clear and white, with no inclusions. Another 2% exhibit some colour, including clear yellow. About 81% are octahedrons and dodecahedrons, 11% are multiple crystals and aggregates, and only 8% are fragments.
The project sat idle for most of 1998 and 1999, until Jonathan Challis, a former vice-president of Ivanhoe Capital and mining analyst with C.M. Oliver, was appointed in June of last year as president and director of Shore. In December, the company completed a $250,000 private placement consisting of 1.25 million flow-through shares price at 20 each.
Shore began a delineation drilling program on the Star anomaly in January 2000 by stepping out 700 metres south of past holes 96-3, 97-3A and 97-3B; it encountered 46.5 metres of the main kimberlite zone in the first hole. The second hole was collared 300 metres south of hole 1 and intersected 26.2 metres of kimberlite. This compares with a 20.2-metre interval intersected in past hole 96-4, a further 450 metres to the south.
The initial 10 holes have widely targeted the central and southern areas of the 2,000-by-1,500-metre magnetic anomaly, intersecting kimberlite in each of the holes. The kimberlite is described as being crater facies with abundant garnet and ilmenite indicator minerals. A thicker wedge of kimberlite, wider than 100 metres, has been intersected by three holes in the west-central portion of the anomaly along a north-south distance of 400 metres. Hole 9 cut 122 metres, hole 4 pulled 116.2 metres, and hole 7 hit 127.4 metres of kimberlite.
The company has hired John Gurney of South Africa-based Mineral Services to supervise all aspects of sampling and analysis. Approximately 200 kg will be shipped to South Africa for analysis, while the bulk of the samples will be processed by an independent Canadian laboratory.
Shore plans to drill a further 10 holes, including five NQ holes and five of the larger-diameter PQ holes. The NQ drilling will target the northern extension of the anomaly, as well as some outlying targets that may or may not be related to the main anomaly, whereas the PQ drilling will be used to take a larger sample in the thicker west-central block.
“We’re still trying to come to grips with whether there is a direct feeder under this very large aeromag anomaly,” says spokesman Doug Ramshaw. “All previous drilling to this year indicated sort of a 40-metre thickness to the kimberlite flow. We are very encouraged with getting some thicker intervals farther to the west.”
The core will be logged to determine if there are facies changes. “There is a lot of talk of fluvial reworking because these things intruded into inland seas,” says Ramshaw. “The key is to determine whether we have hypabyssal or preserved diatreme on-site, or whether these are narrower feeder structures, and what were looking at is a very large re-worked kimberlite.”
The company closed a $300,000 private placement (1 million shares at 30 each) to offshore subscribers in early March and currently has about $350,000 in cash, with 17.8 million shares outstanding. Shore has been trading at $1.45-90, having recently come off a $2 high.
Fort la Corne
At the neighbouring Fort la Corne project,
Fort la Corne is a joint venture, with Kensington and Monopros each holding a 38% share.
The Fort la Corne project area covers of 255 sq. km and contains 69 confirmed kimberlite bodies, 49 of which are diamondiferous, with 34 having yielded stones larger than 1 mm in at least one dimension. Based on geophysical modelling and limited drilling, the surface areas of the individual bodies range from 2.7 to 184 ha, with tonnages estimated at 3 million to 675 million tonnes.
During the 1999 program, four large-diameter (11.75-inch) reverse-circulation holes recovered 64 tonnes of sample from kimberlites 147 and 220, which join with other bodies to form a mega-cluster.
Composite grab samples collected over both 1- and 6-metre intervals of the holes were analyzed in South Africa by Monopros’s parent company,
X-ray analysis
At a joint-venture meeting last August, Monopros reported the recovery of 58 macros larger than 1 mm from the X-ray concentrate — half the number expected. As a number of stones were recovered from the 1997 X-ray tailings, all the 1999 X-ray tailing material was visually examined, leading to the recovery of a further 69 stones.
A Saskatchewan Energy and Mines report highlighting exploration and development in 1999 states: “The diamonds recovered in the 1999 X-ray tailings have unusually low luminescence values, which are lower th
an the detection limit of the X-ray recovery unit, and this explains the large number of stones reported in the tailings.”
Previous work on the 147 body had yielded 58 micros from 34 kg of sampled drill core. A 20-tonne mini-bulk sample had returned 1.5 carats of diamonds, giving a preliminary grade of 7.5 carats per 100 tonnes.
The 220 kimberlite was last drilled in 1997. Microdiamond analysis of 78.4 kg revealed 159 stones weighing 0.039 carat, including a 1.66-mm clear yellow diamond. A further 15.4 tonnes of drill sample returned 20 macros weighing 1.27 carats, including a 0.7-carat stone described as white with abundant inclusions. A preliminary grade of 4.6 carats per 100 tonnes was calculated based on a theoretical mass of 27.5 tonnes.
Early-stage valuations were conducted in 1998 by Antwerp, Belgium-based Luc Rombouts of Terraconsult on a small parcel of 720 stones weighing a total of 37.3 carats. The average value was estimated at US$32 per carat, based on prices at the end of 1997.
Ashton
In the meantime,
The three new discoveries were made on the central Buffalo Hills claim block. The K-252 body contains two distinct phases consisting of fine-to-medium-grained volcaniclastic kimberlite and kimberlite breccia. It was discovered under 67 metres of overburden 1 km northwest of the diamond-bearing K-6 kimberlite. Mini-bulk sampling work in 1997 on K-6 yielded 0.876 carat of diamonds from an aggregate 13.95-tonne sample, for a preliminary grade of 6.31 carats per 100 tonnes. The largest stone recovered was a clear yellow diamond weighing 0.76 carat.
The K-8 kimberlite was found beneath 38 metres of overburden, with a magnetic signature measuring 300 metres in diameter. Kimberlite K-160 is covered by 40 metres of overburden and has a magnetic signature 100 metres in diameter. Samples from the new discoveries will be processed at Ashton’s North Vancouver lab. Microdiamond results are expected sometime during the second quarter.
In the K-14 cluster area, Ashton collected 1 tonne of drill core from kimberlite BH-225, which was discovered in February 1999, about 1 km north of K-14, and which has returned encouraging microdiamonds results. BH-225 is found under 34 metres of overburden, with a magnetic signature measuring 125 by 100 metres. A 96.4-kg sample yielded 62 micros and five macros exceeding 0.5 mm in one dimension, which, according to Ashton, is one of the better results of the Alberta kimberlites.
Ashton drill-tested two magnetic anomalies on the Caribou Mountains property. An iron-rich rock intersected at anomaly CM-1 was determined to be sedimentary in origin, whereas the CM-5 anomaly was caused by magnetic material in the overburden. An anomaly on the Rabbit Lake property was caused by magnetite in the sedimentary bedrock.
Three partners
The Buffalo Hills project is a joint venture among Ashton,
The K-14 project area is covered under a separate arrangement, with Ashton and Alberta Energy each holding a 42.7% stake, whereas Pure Gold owns 14.6%.
The outlying 6.1-million-acre Cayo package, which includes the Caribou Mountains property, is held 35.6% by Ashton, 35.6% by Alberta Energy and 28.8% by Pure Gold.
In early March, Ashton and Pure Gold entered into an option agreement with
The property is 90 km southwest of the K-14 cluster and covers 51.2 sq. km. Ashton drilled one anomaly on the property and determined the source to be magnetic overburden.
Elsewhere in the Buffalo Head area of northern Alberta,
The targets have been selected based on:
– detailed low-level helicopter-borne magnetic geophysical surveys;
– association with interpreted geological structures; and
– proximity to highly anomalous quantities of indicator minerals recovered from the shoreline of Calling Lake, including 62 of the total 66 G10 garnets recovered from the property.
Buffalo can earn an initial half-interest in the property from
In early March, Buffalo arranged a $460,000 private placement comprising 2.3 million units priced at 20 per unit.
New Claymore recently completed a 3-hole winter drilling program on its Steen River prospect in the northwestern corner of the province, some 50 km south of the Northwest Territories border. Drilling tested three widely spaced magnetic anomalies. New Claymore reports that it intersected a brecciated magnetite-bearing rock with volcanic characteristics at roughly 215 metres in each of the holes. Portions of the core have been sent for petrographic analysis to determine the rock type.
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