De Beers to test unusual diamond occurrence at Festival

The Canadian exploration division of De Beers Consolidated Mines, now a subsidiary of Anglo American (AAUK-Q), will process a 100-tonne sample from the Cristal showing on the Festival diamond property, near Wawa, Ont. The property is held by Pele Mountain Resources (YPN-V).

The bulk sample was taken from an outcrop of diamond-bearing, pyroclastic ultramafic breccia rock near the centre of the showing. The sample will be crushed to minus 12 mm and shipped to De Beers’ processing facilities in Grande Prairie, Alta., for macrodiamond analysis. De Beers will process the sample free of charge, with results expected by mid-December.

The Cristal showing consists of various mica breccias and pyroclastic facies of rock that, according to Pele, indicate large explosive maar-like volcanic complexes. The breccia facies make up the base of the unit, and the pyroclastics represent the top, with ash tuffs increasing in proportion toward the upper contact. The showing measures at least 200 metres in width. Pele has stripped off and exposed most of the showing.

“This is a curious occurrence,” states Pele President Al Shefsky. “It is an Archean-age deposit occurring in a cluster of large bodies. We haven’t drilled them yet, but, just looking at the strike length and the width, it’s clear that we’re dealing with major tonnage.” Another showing, called Dom Perignon, has an indicated strike length greater than 1 km.

Surface sampling of all facies of the Cristal prospect has shown that the unit is diamondiferous. Fifteen samples weighing a total of 171.3 kg yielded 327 microdiamonds from all sieve-size fractions up to and including 0.6 mm square mesh. At least 10 stones exceed 0.5 mm in one dimension. The best results have come from samples taken near the contact between the pyroclastics and more brecciated material. Three samples, weighing a combined 39.4 kg, returned 159 micros. The 100-tonne bulk test sample was collected in the immediate area of these samples from a 10-by-10-metre section.

According to Shefsky, the size distribution of the recovered microdiamonds suggests the potential for large, commercial-size stones.

Nine showings

Cristal is just one of nine new showings discovered by Pele on the Festival property in 2001. The Dom Perignon showing yielded 434 micros (including 12 stones exceeding 0.5 mm in one dimension) from a composite 100-kg sample. The largest diamond recovered measured 1.16 by 0.67 by 0.56 mm. The composite sample consisted of 10 smaller individual samples collected across a width of 90 metres.

Discrete, crudely zoned layers of fine-grained, mica-rich groundmass, with variable proportions and sizes of felsic and mafic fragments, characterize the Dom Perignon occurrence.

Independent consultant Edward Walker says the results of geological and structural mapping program by the Ontario Geological Survey reveal that a cluster of diamond-bearing maar volcanic complexes erupted through the Archean-age mafic volcanics. This sequence of rocks was folded and metamorphosed during the Archean period. Subsequent faulting and erosion of the overturned fold limb has repeatedly exposed “corridors” of diamondiferous rocks across the Festival property.

Walker says results from last year’s exploration indicate the presence of at least five separate maar volcanic complexes.

States Shefsky: “We’re on to a brand new type of host rock that is different from the original lamprophyre-type host rocks which first attracted diamond interest in the Wawa area. The purpose of the 100 tonnes is just to demonstrate that there are commercial-size diamonds.”

Discovery

The Festival property ties on to the northern and western boundaries of the GQ property, where, just 1.5 km south of Pele’s Cristal showing, Band-Ore Resources (BAN-T) has made a significant diamond discovery. A diamond-bearing breccia unit was traced in outcrop and by trenching over a strike length of 325 metres and a width of up to 85 metres. Thirteen samples weighing 430 kg were found to contain more than 12,000 micros, including 340 stones greater than 0.5 mm in at least one dimension.

A 12.5-tonne sample taken earlier this spring from the new showing (first christened Area E, then renamed the Engagement zone) returned a parcel of 30 diamonds weighing 0.607 carat. The largest stone was a broken, 0.254-carat, white octahedron measuring 3.74 by 3.3 by 3.1 mm. The other 29 diamonds were of various colours and ranged in size from 0.7 to 3.06 mm in their longest dimension.

Band-Ore has received expressions of interest for the GQ property, as well as the Thorne gold property, near Timmins, Ont., and has begun joint-venture discussions.