Starfield advances Ferguson Lake
By Thomas Schuster
Rankin Inlet, Nunavut -- Recently cashed up and determined to expand resources at its Ferguson Lake copper/nickel/cobalt/platinum-group-metals property in Nunavut, Starfield Resources (SRU-V) is churning out a continuous stream of encouraging drill results. The current program is expected to span 40,000 metres.
Situated west of Rankin Inlet and 160 km southwest of Baker Lake, in the Kivalliq region, the 38-sq.-km property is in an area of low relief and numerous small lakes. The camp occupies a large island in Ferguson Lake that is serviced by an airstrip.
"We have put about $10 million into the property, which includes exploration and property payments," said Starfield President Glen Indra, who spoke with The Miner during a site visit.
The company has $700,000 in its coffers and recently announced a private placement financing worth $2.5 million.
There is little infrastructure in this remote part of Nunavut, apart from abundant water supplies. Starfield has been sourcing its equipment and supplies from Thompson, Man., and Yellowknife, N.W.T. The Nunavut government is considering extending a road through the region from northern Manitoba.
The tree line is 150 km to the south, and vegetation consists of moss, lichen and dwarf birch. The bedrock is well-exposed on numerous low hills and ridges, and elevations vary from 150 to 200 metres above sea level.
The climate boasts long winters, lasting from October through to the end of April, with temperatures averaging minus 31°C. Summer temperatures average 15°C.
The nickel-copper-cobalt-PGM mineralization is hosted in a west-trending, north-dipping, metamorphosed gabbroic unit with hornblendite bands. The unit is believed to be conformable with the enclosing Archean-aged, hornblende-rich gneisses. The gabbro is thought to represent a metamorphosed sill that post-dates the principal deformation in the gneissic rocks. The principal mineralized unit measures between 50 and 200 metres thick and has been traced east and west of Ferguson Lake via bedrock exposures and by diamond drilling over a strike length of 10 km. The unit has been sub-divided into three principal zones: East 1, East 2 and West.
Starfield's 2000 drilling campaign extended the West zone by 2.4 km and traced it to a depth of 1,400 metres. The zone remains open to the west.
Last year, the junior discovered the "M" zone, a flat-lying geophysical target 400 metres wide and more than 2 km long. It lies south of the East zone. Five holes targeted the area, one of which hit 32 metres of mineralization, while the remaining four encountered only narrow intervals. The company believes that these holes intersected the margins of the zone, and more drilling is planned.
Several smaller targets also exist in the area, including Anomaly 51, south of the M zone, and an area south of the West zone. Only limited work has been performed in these areas.
This year's drilling has delineated a large, high-grade area within the West zone, between lines 5600 and 5960 (a distance of 360 metres). The West zone has been drill-tested over a total distance of 2.6 km and still boasts about 2.5 km of undrilled strike. Geophysical surveys indicate that the mineralization continues downdip.
The final three holes drilled last year, nos. 65, 66 and 67, pierced the high-grade zone, and subsequent calculations added 3.3 million tonnes to the West zone resource. This resource, which was last updated in late January 2001, hosts 28.2 million tonnes grading 0.85% copper, 0.56% nickel and 1.27 grams combined platinum and palladium.
The total resource at Ferguson Lake, including the East and West zones, tallies to 32.4 million tonnes grading 0.86% copper, 0.59% nickel and 1.26 grams combined platinum and palladium. Recent drill results are expected to increase the tonnage greatly.
A higher-grade portion of the West zone deposit hosts 8.5 million tonnes grading 1.06% copper, 0.78% nickel and 1.84 grams combined platinum and palladium. These calculations used a cut-off grade of 1% copper and nickel. The ratio of palladium to platinum is about 8-to-1.
Consistent grades
Starfield began this year's drill season by stepping-out 120 metres east of previously reported hole 67 in order to drill holes 68 and 69. Hole 69 was drilled 80 metres downdip of hole 68. Both holes intersected consistent grades in the range of 0.7%-1.8% copper, 0.7%-1% nickel and 2-to-3.2 grams combined platinum and palladium over 14-26 metres.
The next hole, 70, was drilled 80 metres downdip of hole 67 and intersected 5.4 metres grading 1.28% copper, 0.77% nickel, 0.092% cobalt, 1.68 grams palladium and 1.15 grams platinum. A dyke was encountered at the base of this hole and terminated in mineralization.
Holes 71 and 72 were drilled from the same drill pad, 122 metres west of hole 67. Hole 71 was drilled at an angle of minus 65° and intersected 7.24 metres grading 0.9% copper, 0.44% nickel, 0.055% cobalt, 1.14 grams palladium and 0.28 gram platinum, starting at a down-hole depth of 336 metres.
Hole 72 was drilled at minus 85° and undercut hole 71 about 200 metres downdip. It intersected 32.77 metres of 1.01% copper, 0.5% nickel, 0.06% cobalt, 1.3 grams palladium and 0.18 gram platinum, starting at 480.5 metres down-hole. This intersection included a 14.6-metre interval of 1.27% copper, 0.82% nickel, 0.096% cobalt, 2.09 grams palladium and 0.23 gram platinum.
The most recently completed hole, 74, tested the mineralized interval between holes 71 and 72. This hole cut an impressive 64.5 metres of mineralization, starting at a down-hole depth of 370.3 metres. The hole averaged 0.96% copper, 0.53% nickel, 0.064% cobalt, 1.4 grams platinum and 0.24 gram palladium, and included a 17.07-metre interval that assayed 1.19% copper, 0.88% nickel, 0.105% cobalt, 2.2 grams palladium and 0.39 gram platinum.
Hole 73 was drilled to test the mineralization downdip of hole 70, and intersected the following four intervals of mineralization ranging from 1.16 to 7.2 metres in width and starting at a down-hole depth of 579 metres:
- 1.16 metres grading 0.52% copper, 1.09% nickel, 0.13% cobalt, 5 grams palladium and 0.28 gram platinum;
- 7.17 metres grading 1.22% copper, 0.64% nickel, 0.079% cobalt, 1.64 grams palladium and 0.16 gram platinum;
- 1.22 metres grading 2.52% copper, 0.29% nickel, 0.043% cobalt, 1 gram palladium and 0.98 gram platinum;
- 1.74 metres grading 1.3% copper, 0.71% nickel, 0.083% cobalt, 1.65 grams palladium and 0.03 gram platinum.
Currently, Starfield is drilling holes 81 and 82 in the West zone and processing holes 75-80.
Copper and nickel mineralization was first discovered at Ferguson Lake in 1950 by the Canadian Nickel Co. (Canico), an exploration arm of Inco (N-T). Canico explored a 3,000-sq.-km concession by means of airborne and surface geophysics, geological mapping and 37,000 metres of diamond drilling.
About 27,000 metres of drilling were focused on zones east and west of Ferguson Lake and on the intervening area beneath the shallow lake. Inco outlined a copper-nickel resource of about 6.4 million tonnes averaging 0.87% copper and 0.75% nickel. Drilling was performed on 120-metre line spacings. Drill logs and assays are available, though Inco's core was not preserved.
In 1953, the major extracted a 10-ton bulk sample from the West zone and sent it to Copper Cliff, Ont., for testing. However, the results were never released. In 1957, the company acquired a mining lease that covered the central 4,180 ha of the original concession, and in 1978, the lease was reduced by 50%.
Enter Homestake
In the early 1980s, Homestake Mining (HM-N) began sniffing around the area for platinum group metals and, in 1986, staked several claims and prospecting permits around the existing Inco lease. Homestake then sampled the Ferguson Lake property and identified anomalous platinum-palladium values in both bedrock and soil samples collected on and near the previously identified resource. Soil sampling yielded assays of up to 3.7 grams platinum and 15 grams palladium per tonne, whereas chip samples returned 2.8 grams platinum and 5.6 grams palladium. But Homestake allowed the claims to lapse shortly thereafter, and Inco's mining lease expired in June 1992.
"Inco drilled a series of shallow holes that stopped intersecting the West zone," said John Nicholson, Starfield's project geologist. "The zone plunges off to the west, and Inco thought it was faulted off and was gone."
Activity in the area was revived in 1997, when the Ferguson 1-3 claims were staked over the old mining lease. The Ferguson Lake Syndicate re-established the old Inco baseline grid and prospected the area the following summer.
Starfield Resources entered the picture in early 1999 by inking a deal with the Ferguson Lake Syndicate for a 100% interest in exchange for $75,000 and 4.25 million shares. The deal is subject to a 3% net smelter return royalty.
Starfield established a grid and performed both ground and aeromagnetic surveys, as well as geological mapping, prospecting and 4,000 metres of diamond drilling in 19 holes. The following year, the company expanded its geophysical surveys and testing four mineralized zones with an additional 15 holes (3,595 metres).
Geology
The Ferguson Lake property is near the western margin of Hearne province, a subdivision of the larger Churchill structural province of the Canadian Shield. Hearne province hosts highly deformed, and reworked Archean- and Proterozoic-aged gneisses, granites and supracrustral rocks.
The oldest rocks in the Ferguson Lake area are the Archean-aged greenstone belts, which trend in a northeast-to-east direction and consist of mafic metavolcanics, cherty iron formations and, to a lesser extent, felsic metavolcanics and clastic metasedimentary rocks.
The property itself is underlain by east-to-northeast-trending gneisses cut by dykes and small intrusions. The mineralized host unit has been described as a massive-to-weakly-foliated hornblendite unit with a small peridotite body marginal to it.
"After looking more carefully at the host unit, we have concluded it is a gabbroic sill with an ultramafic constituent," said Nicholson. "Much of what we've been calling an amphibolite is probably gabbro with some hornblendite bands. The massive sulphide lenses range from several to more than 20 metres thick and are stacked."
The sulphide-bearing sill is thought to have been emplaced along east-to-northeast-trending fault zones. The intrusion is locally offset by later, north-trending faults.
Mineralogy
The dominant sulphide mineralization in the hornblendite host rock consists of pyrrhotite, pyrite and chalcopyrite, which occur as massive pods and lenses, as well as stringers and veinlets. Associated magnetite can be observed as blebs, though pentlandite cannot be seen with the naked eye.
Only a limited amount of mineralogical work has been performed on the sulphides, and no metallurgical data are available. Three drill-core sections from the West zone and two from the East zone were analyzed by Cominco Exploration Research Laboratories for ore microscopy. Results indicate that all the samples consisted of pyrrhotite (80-90%), with a lesser abundance of magnetite (7-17%), chalcopyrite (1-8%) and pentlandite (2-3%). The pentlandite was observed to occur as small, micron-sized-grains at pyrrhotite grain boundaries, as well as flame-like intergrowths in the pyrrhotite.
Scanning electron microprobe work identified moncheite, a mineral associated with platinum, palladium, tellurium and bismuth. The moncheite measures 5-30 microns in the pyrrhotite and is adjacent to magnetite blebs. Also identified was gersdorffite, a nickel-cobalt-arsenic sulphide mineral associated with pyrrhotite. These findings are preliminary.
Starfield recently negotiated a $2.5-million private placement financing with an Austrian syndicate. The financing will consist of 3.8 million units, each of which consists of one share and one warrant. The warrant grants the holder the option to buy an additional share at $1 over one year, effective July 1. Also, the syndicate can buy an additional $2.5 million worth of units within 90 days of July 1.
At last report, Starfield had 35 million shares fully diluted. |
