Results from a 7,000-tonne bulk-sampling program by
The progam was focused on the Victor kimberlite, which occurs in a cluster of 16 pipes discovered in the late 1980s by Monopros (now De Beers Canada Exploration), 90 km west of the First Nation community of Attawapiskat. All but one of the kimberlites are diamondiferous. Subsequently, in 1994, two additional small kimberlites were discovered by
An initial 330-tonne mini-bulk sample of the Victor kimberlite, taken last year, yielded 107.9 carats of diamonds, with a value of US$16,590. De Beers revealed this information at a public session held earlier in the year at Attawapiskat. The mini-bulk sample results suggest a preliminary grade of 0.33 carat per tonne, a diamond value of US$154 per carat and a kimberlite value of US$50 per tonne.
The Victor kimberlite is composed of two pipes that coalesce at surface, covering an area of more than 15 ha. The Victor bodies are covered by at least 6 metres of glacial and marine till.
Spider Resources and KWG discovered seven intrusive bodies between 1993 and 1997 in the James Bay Lowlands. These included the two MacFayden kimberlite pipes at the northern end of the Attawapiskat cluster, as well as five intrusive bodies known as the Kyle Lake series. Ashton was involved in the early days of this joint venture but opted out in 1996.
Kimberlites in the Attawapiskat cluster occur at the southern end of the Winisk River fault and are oriented in a northwest fashion parallel to the strike of the fault.
The Kyle series of bodies lies west of the Winisk River fault and are Proterozoic, or 1.1 billion years old. The Attawapiskat kimberlites are early Jurassic, or 154-180 million years old.
The Kyle Lake 1 body was discovered in 1994, 100 km southwest of the Attawapiskat swarm, by using data derived from aeromagnetic surveys and structural analysis. The Kyle series consist of deep-lying bodies. Kyle Lake 1 is covered by up to 135 metres of Paleozoic sediments and overburden. The joint venture estimates that Kyle Lake 1 has a surface area of 2.6 ha and contains some 14.5 million tonnes of “kimberlite” to the 510-metre level, based on 18 holes.
Experts disagree as to whether the Kyle bodies are true kimberlites. Several specialists have examined the core and offered differing opinions. One expert stated it was not kimberlite but, rather, some form of a lamprophyre. Another suggested that the intrusive is a hybrid, falling somewhere between an alnoite and a kimberlite, whereas yet another suggested that the surrounding granite gneissic terrain had contaminated the intrusive body.
In all, 6.2 tonnes of sampled core yielded 3,602 microdiamonds and 793 macros (a macro is here defined as measuring greater than 0.5 mm in at least one dimension) for a combined total weight of 3.71 carats.
This spring, Spider resumed exploration on the Kyle Lake 3 body and completed seven additional holes. Kyle Lake 3 is 100 km northwest of Kyle Lake 1 and 120 km due west of the Victor kimberlite. It was discovered in 1995 and initially tested by five holes.
The Kyle Lake 3 body is interpreted as a complex, multi-phased diatreme intrusion, with numerous dykes emanating out from it in all directions. One particular east-west-striking dyke has been shown to have an elevated diamond count. It extends 450 metres along strike and is 4-6 metres thick.
The first five holes from this year’s program returned 711 micros and 35 macros from 1,123 kg of sample. To date, the Kyle Lake 3 body has yielded 863 micros and 58 macros from a total of 1,804 kg of sample material. Micro results are pending for 39 remaining samples from the final two holes of the 2000 program.
Early in the year,
Navigator can earn a half-interest in the project by spending $1.7 million over two years. The company is also the operator. Based on a review of regional airborne magnetic data, the partners staked 150 sq. km of ground, referred to as the Kat claims, in the immediate vicinity of the Attawapiskat cluster. In addition, the 12-sq.-km Ogoki claim block was staked to cover five specific magnetic anomalies, whereas the 50-sq.-km Caribou block was staked in a region that returned positive indicator minerals based on the 1999 sampling. The Caribou claims also cover strong, isolated magnetic responses identified from regional airborne data.
Navigator has completed 38,200 line km of airborne magnetic surveys. The best targets will be drilled after freeze-up in late 2000 or early 2001.
Another junior active in the area is
Two other principle areas of kimberlite discovery and exploration activity in Ontario are Wawa and Kirkland Lake-New Liskeard.
Wawa
In 1991, local prospector Mickey Clement pulled three diamonds from the riverbed of the Dead River ox-bow in Michipicoten River, immediately south of Wawa. Two of the stones were later identified by the Royal Ontario Museum as industrial grade, with weights of 1.05 and 1.13 carats. When word of the discovery reached the ears of Ronald Sage at the Ontario Geological Survey (OGS) some two years later, he and fellow OGS geoscientist Thomas Morris carried out preliminary sampling of sands and gravel in and around Dead River and Wawa Creek. Ten samples yielded nine chrome diopsides and one G10 pyrope garnet.
In 1995, prospector Sandor Surmacz and geologist Marcelle Hauseux sampled an outcropping actinolite-rich lamprophyre dyke along Highway 17, about 30 km north of Wawa. Their initial 18.1-kg sample yielded five micros and one macro. Spider and KWG optioned the discovery in early 1996 and went on to find seven more diamond-bearing, lamprophyre outcrop occurrences within a 5-sq.-km area of the 45-sq.-km property. The original Sandor discovery has yielded a total of 82 micros and 15 macros from 309.3 kg of surface sampling. The largest stone measured 0.65 by 0.62 by 0.4 mm.
An outcrop 3.9 km south of the Sandor discovery site yielded 87 micros and 16 macros from 193 kg of material. There, the largest recovered stone measured 0.91 by 0.42 by 0.38 mm.
There have since been dozens of lamprophyre dyke occurrences discovered along the northwest-striking Highway 17 corridor. Speaking at a recent diamond symposium in Toronto, Sage said the dykes consist of basalt to mildly alkalic basalt composition and contain large xenoliths of talc-actinolite-carbonate. The Archean-age dykes are diamondiferous but lack the kimberlite indicator mineral suite and cannot be traced by geophysical techniques. The dykes occur only in the northwest portion of the Michipicoten greenstone belt and appear to be restricted to a northwest-striking, 10-km-wide corridor that extends for up to 20 km of distance from Musquash Twp.
Other juniors active in this corridor include
Band-Ore secured a 100% interest in the 25-sq.-km GQ property at the first of the year after prospectors discovered several showings of diamond-bearing fragmental lamprophyre material that had been exposed by construction of new logging roads. The GQ northern property boundary is 1 km southeast of the Spider-KWG joint venture.
A 63.4-kg sample from one of the new showings yielded 35 micros and 10 macros, including one stone measuring greater than 1 mm in one dimension. A 70.5-kg sample from a second outcrop, 500 metres away, returned nine micros.
During the summer, Band-Ore identified five major zones of heterolithic breccia in outcropping areas. Two of the breccia zones have been traced for more than 1.6 km in length, with widths varying from 1.5 to more than 50 metres.
In May, the junior completed three short drill holes in the area of the original discovery. The first two holes, collared 70 metres apart, yielded 521 micros and one macro from 219 kg of breccia material. One sample weighing 30.3 kg accounted for 434 of the stones. A 7.5-kg sample from the third hole returned one brown macro and four micros.
In total, 732 micros and 15 macros have been recovered from 785 kg of sample material collected from a 75-metre strike length along the main showing. Most of the stones recovered are white, clear and transparent.
Band-Ore sampled more than 100 surface showings during the summer and fall, to collect 177 samples weighing 5.3 tonnes. The Saskatchewan Research Council, which is analyzing the samples for microdiamonds, reports that two of the first four samples processed were positive. A 32-kg sample taken 1.5 km northeast of the original discovery contained nine micros, whereas a 48-kg sample, 2 km to the northwest, yielded two micros.
Results from all samples are expected to be completed by early February.
Dumont Nickel has identified 35 lamprophyre showings on its 77-sq.-km property, 25 km north of Wawa and 6 km northwest of Band-Ore’s GQ property. To date, samples from only two of the lamprophyres have been analyzed for diamonds. A 49.2-kg sample contained 12 micros, of which 11 stones were described as yellow fragments.
A second, 56.7-kg sample, taken from a micaceous 5-metre-wide lamprophyre, contained no diamonds. Dumont also holds ground in the James Bay Lowlands in joint venture with
In May, Pele Mountain, acquired the exploration rights to the 12-sq.-km Festival property, 25 km north of Wawa. It soon recovered a yellow diamond measuring 0.68 by 0.68 by 0.39 mm from a 35.2-kg surface sample of the Jubilee showing. Analyses of a further 110 kg of sample yielded no diamonds.
A second showing, 4 km to the southeast, yielded one macro and 63 micros from about 345 kg of weathered residue. A hard-rock sample weighing 53 kg returned one micro. The showing, known as “Destiny,” consists of xenolithic facies of lamprophyre. It sits just 1.7 km east of Spider’s Sandor showing.
Hypabyssal kimberlite has been identified in the Wawa region in association with thrust faulting resulting from the development of the Kapuskasing structural zone. So far, these kimberlites have proved barren. Even so, Sage remains optimistic about the area’s potential.
“The presence of abundant kimberlite indicator minerals, float diamond and the discovery of several kimberlite intrusions in the Wawa area indicate that the southern end of the Kapuskasing structural zone, where it intersects the Mid-continental Rift, is a good region in which to seek kimberlite,” concludes Sage.
Kennecott Canada Exploration, a subsidiary of
Kennecott can earn a 60% interest in the 36,440-sq.-km package by spending $25 million on exploration over seven years. The joint venture covers Canabrava’s wholly owned Whitefish Lake project, plus the KAP and Rocky Island Lake projects, which are owned 50-50 by Canabrava and Paramount.
Kennecott initially carried out follow-up sampling in high-priority areas and additional regional reconnaissance sampling on the Rocky Island Lake project. A helicopter-borne magnetic-electromagnetic survey was flown over priority areas of the Whitefish Lake project in January 2000. This was followed by a winter program of ground geophysics over 21 targets on the Whitefish property and over two targets on the KAP central claims.
A drilling program was cut short by the early onset of spring weather conditions. Only five targets were drilled before the program was abandoned, owing to poor ice conditions. No kimberlite was intersected, though Kennecott did encounter several intervals of ultramafic lamprophyre.
Exploration on the Whitefish and Rocky Island Lake projects has been ongoing through the summer and fall. Kennecott has focused on localized high-density grid sampling over prospective targets in preparation for further geophysics and drilling. On the Rocky Island project, several kimberlitic boulders were identified in an anomalous area of indicator minerals.
Other juniors active in the area include
Tri-Origin collected an initial 10 samples of dyke material from old core and surface outcrops. Microdiamond analysis indicated the material was barren.
Kirkland Lake region
Approximately 30 kimberlite occurrences, diatremes or dykes have been recorded in the Kirkland Lake area. While most were shown to be diamondiferous, the grades are generally low.
Daniel Schulze of the University of Toronto, speaking at a recent diamond symposium held by the Toronto Geological Discussion Group, said the indicator mineral chemistry of eight Kirkland Lake pipes was consistent with the presence of diamonds but that it was also consistent with low diamond counts. “G10 garnets are not abundant nor very low in calcium oxide, and relatively few chromites have been found that correspond to those from the diamond inclusion field,” states Schulze. “Most ilmenites apparently belong to the chromium-poor megacryst suite.” He added that the indicator mineral chemistry of the Attawapiskat pipes is comparable to that of the Kirkland Lake pipes.
The first recorded kimberlite discovery in the Kirkland Lake was made in 1946 in drill core from the property of Marchaud Mines, in Michaud Twp. Renzy Mines intersected kimberlite in the same area in 1970.
Lac Minerals and Monopros discovered eight kimberlite pipes in the mid-1980s while drill-testing airborne geophysical anomalies in Bisley-Gauthier Twp., east of Kirkland Lake. Monopros found a ninth pipe in the New Liskeard area. Five of the kimberlites were diamondiferous. Dia Met Minerals subsequently drilled several of these properties.
The kimberlites in this region are Jurassic in age, spanning 30 million years or more in emplacement. They occur along major northwest-striking faults parallel to, or branching off from, the Lake Timiskaming zone. “The Lake Timiskaming structural zone from North Bay to Kirkland Lake should host many more yet-to-be-discovered kimberlite intrusions,” said Sage.
There are only a few juniors active in the Kirkland Lake area.
Elsewhere in Ontario,
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