November 15, 2007 14:02 ET

Great Western Diamonds Corp.: Progress Report for Diamond Recovery at SRC Dense Media Plant

SASKATOON, SASKATCHEWAN--(Marketwire - Nov. 15, 2007) -


Great Western Diamonds Corp. ("GWD" or the "Company") (TSX VENTURE:GWD) is pleased to announce significant progress made on processing of kimberlite minibulk samples collected during the winter of 2006-07 from the Candle Lake C29/30 Kimberlite. Diamonds from a total of 498 tonnes of kimberlite will be recovered down to a nominal size of 1 mm in the newly-commissioned dense media separation (DMS) plant operated by the Saskatchewan Research Council (SRC) in Saskatoon.

Brent Jellicoe, President and CEO of GWD stated, "I am very pleased that over half of the diamond recovery processing has been completed in this leading edge facility. A great deal of experience and expertise was marshalled into the construction and commissioning of the new plant, and I am fully confident that all precautions have been taken to ensure secure, efficient, and thorough recovery of the Candle Lake macrodiamonds."

Drilling and Minibulk Sample Collection

Last winters' field program at Candle Lake involved drilling of 26 PQ coreholes (85 mm diameter) totalling 6,306.22 m covering part of the southern portion of the kimberlite body and along approximately 1000 m of the central axis of the kimberlite body. A subset of these coreholes was utilized as pilot holes for nine large diameter (609.6 mm or 24 inch), reverse circulation drillholes (LDD) of which seven were located on the southern part of the C29/30 kimberlite and two on the central and northern axis of the kimberlite.

A total of 2,215.14 m were drilled as large diameter boreholes with 856.25 m of kimberlite intersected and 497.97 tonnes of +0.98 mm minibulk sample material retained from an estimated excavated mass of 624.77 tonnes (Table 1). Samples will be processed on a 3 to 9 meter interval basis within the boundaries of individual kimberlite units that were determined by detailed description of rock from coreholes twinned by the LDD.

Table 1: Summary of Minibulk Samples from the 2006-07 Candle Lake Large
Diameter Drilling Program

Nominal Total Total Actual
Hole Kimberlite Number Drill Kimberlite Sample
LDD Minibulk Diameter Thickness of Depth Excavated Mass
Drillholes (mm) (metres) Samples (metres) (tonnes)(tonnes)
CL-06-LD-001 609.6 98.78 17 247.77 72.08 49.67
CL-07-LD-001 609.6 114.90 22 263.30 83.84 73.47
CL-07-LD-002 609.6 33.60 8 195.00 24.52 18.55
CL-07-LD-003 609.6 100.55 19 247.90 73.37 61.91
CL-07-LD-004 609.6 87.77 15 234.75 64.04 46.55
CL-07-LD-005 609.6 110.40 19 257.50 80.55 70.81
CL-07-LD-006 609.6 117.44 21 270.61 85.69 68.12
CL-07-LD-007 609.6 99.81 17 253.31 72.83 53.59
CL-07-LD-008 609.6 93.00 17 245.00 67.86 55.49
Totals 856.25 155 2,215.14 624.77 498.16

"Total Kimberlite Excavated" is based on calculated downhole volumes using
estimated kimberlite density value of 2.5.
"Actual Sample Mass" refers to excavated kimberlite chips passing over a
wire mesh screen with openings greater than 0.98 mm and then recovered in
minibulk bags for diamond recovery.

Processing Progress to Date

The dense media plant commenced processing the GWD samples on Sept 13, 2007 after a protracted period of plant construction and commissioning. There are a total of 155 batches to run through the plant with each batch averaging some 4 tonnes in size. At present, the plant operates an average of 14 hours per day for six days a week. A typical daily run will process about 14 tonnes of kimberlite, or an average of 3.5 batches per day. To date, the SRC has processed the following:

- an initial 7 batches (24 tonnes) through first and second pass DMS, caustic fusion, and final sorting;

- 93 additional batches (or some 297 tonnes of total 498 tonnes) through first pass DMS only, of which,

- 52 batches have continued through caustic fusion treatments, of which 41 batches have completed final sorting

The Diamond Recovery Process

During the first pass of processing, samples are washed in a scrubber unit to remove less than 0.85 mm fines and then screened through a trommel to separate chips greater than 12.5mm. This oversize material is crushed to produce chips less than 12.5 mm in size and then re-introduced to the scrubber. All "right-sized" material (nominally +0.85 mm chips) is processed in the DMS unit with a specific gravity cut point of 3.00 to 3.05 g/cm3 and 100% cut at a maximum of 3.25. The plant is rinsed out between batches and there is a major gravel cleanout conducted between lithological zones. DMS tailings from each batch undergo a second pass that includes crushing to 6 mm and re-circulation through the plant to create a second heavy mineral concentrate. All DMS concentrates are collected in individual pails having security seals within in a secure glove box. Recovered DMS concentrates are running between 0.2 - 1% of headfeed mass; (or an average of 6 kg of heavy minerals recovered per tonne of input). The concentrate material from each batch is processed using the SRC Geoanalytical Laboratories high security diamond facility Caustic Fusion method (ISO/IEC 17025:2005 accredited method) to produce a final concentrate that is picked by hand for diamond. Each recovered diamond is then fully described including comments on possible diamond breakage, and weighed before reporting to the Company.

As due diligence, SRC Management provide independent security measures to monitor all stages of processing of the samples. All clean-up material is processed separately. Approximately 15 batches (10%) will be re-run to check heavy mineral returns to DMS concentrate and then diamond recovery efficiencies utilizing caustic fusion and, or hand sorting.

Brent C. Jellicoe, P.Geo., is a Professional Geoscientist in the Province of Saskatchewan and is the Qualified Person responsible for the verification and quality assurance of analytical results.

Great Western Diamond Corp. is an exploration company that is operated on a vision of growth and substantial enhancement of shareholder value based on a balance of management experience, technical expertise, and expansion of operations. GWD currently is focused on the 100%-owned Candle Lake Diamond Project in central Saskatchewan where an aggressive, results-driven evaluation program is targeted on reaching an advancement decision on the Candle Lake kimberlites by the end of 2008. While Candle Lake is the core diamond project, the Company continues to build a balanced and geographically diverse project portfolio with both advanced and grass-root diamond properties in Canada and Brazil.

Brent Jellicoe, P.Geo, President & CEO

The securities being offered have not been registered under the U.S. Securities Act of 1933, as amended, and may not be offered or sold in the United States in the absence of registration or an applicable exemption from the registration requirements. This press release does not constitute an offer to sell or the solicitation of an offer to purchase securities in the United States.

(The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this release)

Contact Information

  • Great Western Diamonds Corp.
    Brent Jellicoe
    (306) 651-8873
    Great Western Diamonds Corp.
    226 Cardinal Crescent
    Saskatoon, SK, S7L 6H8