DIAMOND PAGE — Ashton begins $10-million field program at Buffalo Hills

A winter exploration program is now underway on the Buffalo Hills diamond project in north-central Alberta.

Operator Ashton Mining of Canada (ACA-T) and joint-venture partners Alberta Energy (AEC-T) and Pure Gold Minerals (PUG-T) have set an initial $10-million exploration budget for 1998. Work will include the collection of a minimum 500-tonne bulk sample from the K14 kimberlite complex, mini-bulk sampling of the K91 kimberlite, exploration drilling of at least 15 new targets and extensive airborne geophysical surveys. The budget also includes provisions for the acquisition of a 10-tonne-per-hour dense media separation (DMS) diamond recovery plant.

During 1997, Ashton discovered 15 kimberlite bodies on the original Buffalo Hills property, 11 of which were confirmed to be diamondiferous.

A population of commercial-size diamonds were identified in the K14 complex.

In total, 7.79 carats of diamonds larger than 0.8 mm in size were recovered from an aggregate 44.87-tonne mini-bulk sample from the K14 complex, for an average grade of 17.4 carats per 100 tonnes. The seven largest stones weigh a collective 3.2 carats, representing 41% of the total carat weight. The largest diamond, a 1.31-carat stone, was described as “a single crystal, of silver-grey appearance, with many dark inclusions.”

The K14 complex was first thought to be three separate pipes, but delineation drilling suggests K14 is a single, roughly circular, complex feature that measures about 400 metres in diameter. Kimberlite in the central phase of the body is confirmed to a depth of at least 200 metres. It is covered by just 7 metres of overburden.

The K91 kimberlite lies approximately 2.5 km to the northwest of the K14 complex, beneath 14 metres of overburden. A 0.85-tonne sample collected from four core drill holes yielded a 0.301-carat parcel, for a preliminary grade of 35.4 carats per 100 tonnes. The two largest stones weighed 0.14 and 0.13 carat.

Results to date indicate a high degree of variability in diamond content from hole to hole in both the K14 and K91 kimberlites.

Ashton announced new results from mini-bulk sampling on kimberlite K6, from which a clear yellow stone weighing 0.76 carat was recovered in the early stages of processing. A 5.17-tonne sample from K6 collected from core drilling returned 0.804 carat of diamonds, for a preliminary grade of 15.5 carats per 100 tonnes.

Reverse circulation drilling into K6 recovered 4.13 tonnes of sample, which yielded 0.005 carat of diamonds, equivalent to a grade of 0.1 carat per 100 tonnes. An additional 4.65 tonnes of K6 material was collected from surface pits, returning 0.067 carat of diamonds, giving a grade of 1.4 carats per 100 tonnes.

In total, 0.876 carat of diamonds were recovered from an aggregate 13.95-tonne, mini-bulk sample of the K6 kimberlite, for a preliminary grade of 6.3 carats per 100 tonnes.

Ashton says that although only a few macrodiamonds other than the yellow stone have been recovered from K6, the presence of this stone alone indicates a need for further sampling. Ashton defines a macro as greater than, or equal to, 0.5 mm in at least one direction.

The original 1.4-million-acre Buffalo Hills property, plus 4.4 million acres of surrounding ground, is held 42.5% by Ashton, 42.5% by Alberta Energy and 15% by Pure Gold. A further 22.5-million-acre package is held 49% by Pure Gold, 25.5% by Ashton and 25.5% by Alberta Energy.