DIAMOND PAGE — Buffalo Hills JV puts dense media plant on hold

Ashton Mining of Canada (ACA-T) and its partners in the Buffalo Hills joint venture have deferred construction of an on-site dense media separation (DMS) plant at their diamond project in north-central Alberta. Construction is now scheduled to begin in the spring of 1999 so as to avoid winter conditions.

A 450-tonne bulk sample of the K-14 kimberlite, which was collected and stockpiled last winter, is now being moved to a contract facility for treatment. K-14 is one of 23 kimberlite bodies discovered by Ashton in the central, 1.4-million-acre claim package.

Drilling of angled core holes suggests that K-14 is one large complex measuring roughly 400 metres in diameter. The central pipe is open at depth and flanked to the north and northeast by a thick apron of tuffisitic crater-facies material.

A previous, 44.9-tonne composite sample of K-14, collected from surface pits, reverse-circulation (RC) and core drilling, yielded 7.79 carats of diamonds larger than 0.8 mm in size. The preliminary grade was 17.4 carats per 100 tonnes (0.174 carat per tonne).

The seven largest stones recovered weigh 1.31, 0.6, 0.32, 0.3, 0.28, 0.21 and 0.18 carats, representing 41% of the total weight. The 1.31-carat stone was described as a “single crystal, of silver-grey appearance, with many dark inclusions.” The other six stones are said to be generally clear.

The initial results showed a high degree of variability in diamond content between samples taken from different areas of the K-14 complex, ranging from 2 to 43 carats per 100 tonnes. Ashton said the results demonstrated the need to collect a larger bulk sample for further evaluation.

In all, 16 of the 23 kimberlites found to date are diamondiferous, with four — K-14, K-91, K-5 and K-6 — having undergone mini-bulk sampling. Ashton recently began delineation core drilling on the K-11 kimberlite in preparation for the collection of a mini-bulk sample of 20-25 tonnes using an RC rig. The sample will be processed at Ashton’s DMS plant in North Vancouver.

K-11 is one of nine kimberlites discovered this past winter. A single, vertical, RC hole drilled into the kimberlite yielded an initial count of 14 macrodiamonds and 106 microdiamonds from four samples totalling 189.5 kg, with the largest stone having a maximum dimension of 1.7 mm. (A macro is defined as measuring greater than 0.5 mm in at least one dimension.)

K-11 occurs in a new cluster 30 km east of K-14 and is defined by a magnetic anomaly measuring 500 by 250 metres. The pipe sits beneath 13.4 metres of overburden.

A systematic, follow-up program of ground geophysics has defined an unspecified number of anomalies, and, in the last quarter of this year, regional drilling will be carried out in the surrounding Birch Mountain and Loon Lake properties.

Ashton is operator of the Buffalo Hills project and holds a 42.5% interest in the 1.4-million-acre core group of claims, plus an additional 4.1 million acres of surrounding ground, including the Birch Mountain and Loon Lake properties. Alberta Energy (AEC-T) also holds 42.5%, with the balance held by Pure Gold Minerals (PUG-T).

A broader, 22.7-million-acre package is 49%-owned by Pure Gold, with the balance divided equally between Ashton and Alberta Energy.