Sudbury Contact comes up with diamonds (June 14, 2004)

Sudbury Contact Mines (SUD-T) has processed a mini-bulk sample from one of the kimberlites, 95-2, on its Timiskaming diamond project in Ontario.

So far, Sudbury Contact has located seven kimberlites on its properties, which comprise two leases and 271 claims in the New Liskeard area. The 95-2 pipe is about 20 km west of the town.

A highlight of the current sampling is the size of some of the diamonds. The company sampled 652 dry metric tonnes from six large-diameter holes in 61 mini-bulk samples.

Sampling indicates that the eastern section of the 95-2 pipe is the most diamondiferous and contains the largest diamonds; 12 diamonds exceeded 3.35 mm in at least one dimension and four of these exceeded 1 carat. The largest weighed 1.623 carats. In addition, this part of the kimberlite yielded 54 diamonds on the 2.36-mm sieve and 133 on the 1.7-mm sieve.

The upper weathered tuffisitic kimberlite graded 16.31 carats per 100 tonnes, while the lower eastern tuffisitic kimberlite graded 13.28 carats. These grades were calculated from 420 tonnes of kimberlite. Two samples graded in excess of 35 carats per 100 tonnes.

Diamonds are predominately white and transparent, with less than 10% being brown, pink or yellow. Drilling tested the kimberlite to a depth of 300 metres. The pipe is covered with overburden but has approximate surface dimensions of 400 by 150 metres. It is estimated to contain 15.5 million tonnes of kimberlite to a depth of 300 metres.

The western portion of the pipe is related to a hypabyssal kimberlite, petrographically distinct from the eastern pipe.

The western part of the pipe yielded fewer diamonds, and those recovered were of smaller dimension. Nineteen diamonds were recovered on the 2.36-mm sieve and 38 on the 1.7-mm sieve. This part of the pipe graded 5.49 carats per 100 tonnes in the tuffisitic facies, 4.25 carats per 100 tonnes in the weathered tuffisitic kimberlite, and 3.72 carats per 100 tonnes in a hypabyssal facies.

Samples were concentrated by dense-media-separation techniques with 0.85-mm bottom cutoff screens. Diamonds were recovered using X-rays and a grease table at SGS Lakefield Research. An additional 46 diamonds were recovered as spillage from all facets of the processing; one of these was between 2.35 mm and 3.35 mm in size.

Sudbury Contact holds 265 claims covering more than 360 sq. km in an area straddling Ontario and Quebec. This spring, two kimberlites, KL-1 and KL-22, were discovered on the property, about 20 km southwest of the 95-2 pipe.

Kl-1 was intersected at a down-hole depth of 13.7 metres and remained in kimberlite for the length of the hole (156.4 metres). It is about 5 hectares in size.

The first five samples have been processed, resulting in 2 macrodiamonds and 25 microdiamonds, from a 87.95-kg sample. A total weight of 0.007 carat was recovered. Fourteen of the diamonds were recovered from the upper hypabyssal facies, whereas 13 came from the lower tuffisitic facies. All diamonds were between 0.105 mm and 0.425 mm in size.

Results are pending from the 9.5-hectare KL-22 kimberlite. Kimberlite was intersected at 21 metres, and the hole was terminated in kimberlite at 87 metres.