The history of Canada’s first commercial diamond mine Ekati dates back to the ’80s, when prospectors Dr Charles E Fipke and Dr Stewart Blusson conducted extensive exploration and development work, collecting systematic heavy mineral sampling over a ten-year period. This resulted in the discovery of kimberlites in the Lac de Gras region.
Dia Met Minerals (Dia Met), which was funding the exploration programmes, began purchasing stakes in the region’s mineral claims and approached BHP Billiton as a potential partner in late 1989, after making significant indicator mineral finds in the area.
The Core Zone joint venture (JV) agreement between BHP Billiton, Dia Met, Charles Fipke and Stewart Blusson was signed in August 1990.
The first diamond-bearing kimberlite pipe on the property was discovered in 1991.
BHP Billiton was granted by an addendum to the Core Zone JV in October 1991 to acquire additional mineral claims within 22,500ft from external boundaries of the property area, which eventually became the Buffer Zone JV.
Gahcho Kué diamond mine is located approximately 280km north-east of Yellowknife City in Mackenzie District, Northwest Territories, Canada.
BHP started collecting baseline environmental data for the NWT Diamonds project area (now known as Ekati) in 1993. It submitted an environmental impact statement (EIS) for the NWT Diamonds project to the federally-appointed Environmental Assessment Review Panel in 1995. The Canadian Government approved the development of the NWT Diamonds project in November 1996.
Construction of the mine began in 1997, after reaching an environmental agreement with the Canadian Government and the Government of the Northwest Territories.
The NWT Diamonds project was renamed the Ekati Diamond Mine project in 1998. Open pit mining operations began in August 1998 at the Panda pipe, which continued up to 2003.
Ekati Diamond mine was officially opened on 14 October 1998 and Ekati hit the million tonne production mark in 1999.
Ekati produced 2.77 million carats of diamonds.
A fixed-wing airborne gravity gradiometer survey was conducted over the property to identify new kimberlites.
BHP Billiton increased its stake in Ekati from 51% to 80% by acquiring Dia Met.
Diamond recovery from the Misery pipe, the mine’s second open-pit operation, which started in December.
Production in the financial year rose to 4.56 million carats (grading 1.36c/t).
BHP Billiton started selling Ekati mine diamonds under the Aurias brand name in November.
The Panda open pit mine reached its economic depth in June.
The Koala open pit mine and the Koala North underground trial mine commenced operation during the year.
Diamond production rose to 5.42 million carats (grading 1.26c/t) during the financial year.
The first phase Misery open pit mining operation was completed and the Beartooth open pit operation started.
BHP Billiton announced the approval of the $182m Panda Underground Project in May.
Ekati Mine’s annual diamond production peaked at 6.853 million carats (grading 1.54c/t) during the financial year ending in June.
Underground production from the Panda pipe began in June and was followed by start of open pit mining at the Fox Kimberlite pipe.
The construction of Panda underground mine was completed at the beginning of the year. The first phase of Misery open pit operation was also completed during the same year although production from the Misery stockpiles continued in 2007.
The $220m Koala Underground Project, estimated to produce 9.8 million carats of high value over its eleven year production life, was approved in June.
Ekati’s diamond production further decreased to 3.19 million carats (grading 0.74c/t).
A helicopter borne gravity gradiometer survey was conducted in August to identify the presence of other potential kimberlite pipes in the Ekati property area.
Underground production from the Koala pipe began in June 2007 following the completion of open pit mining of the pipe.
Additional kimberlites were discovered in the Ekati area through drilling conducted at number of target areas identified through the helicopter-borne geophysical survey carried out in 2006. The total number of known kimberlites in the area increased to 150.
Production during the fiscal year rose to 4.030 million carats (grading 0.89c/t).
Ekati’s third underground diamond mine, the Koala Underground Project, was officially commissioned in December.
The Beartooth open pit operation came to an end and the depleted area was converted into tailings storage area for processed kimberlite.
Diamond production during the fiscal year increased to 4.18 million carats (grading 0.95c/t).
Production during the fiscal year decreased slightly to 4.026 million carats (grading 0.85c/t).
Underground production from the Panda pipe was completed and commercial underground mining began at Koala North.
Overall production decreased even further to 3.811 million carats (grading 0.78c/t) during the year.
78ct diamond Ekati Spirit, which is the best quality diamond ever produced at the mine, was discovered.
The $323m second phase of Misery open pit project, scheduled to commence ore production in 2015, was approved in May. Pre-stripping at Misery for the pushback pit was also commenced during the year.
The 78ct Ekati Spirit was sold at an auction.
Ekati’s diamond production during the year fell further to 3.13 million carats (grading 0.67c/t), while the mine reached the 50 million carats production milestone.
On 30 November 2011, BHP Billiton announced it was evaluating the option of selling all or part of its diamond business.
Ekati’s production during the year ending in June slipped to 2.23 million carats (grading 0.50c/t).
In November 2012, BHP Billiton signed definitive agreements to sell its interests in the Ekati Diamond Mine as well as its diamonds marketing operations to Harry Winston Diamond Mines (currently known as Dominion Diamond Corporation) for an aggregate cash consideration of $500m.
The Pigeon surface lease in Ekati’s core zone property area was renewed in December to extend up to 2026.
The total probable reserves at Ekati as of December 2012 were estimated at 19.6 million carats.
BHP Billiton sold all its interest in the Ekati diamond mine to Dominion Diamond Corporation for $553 million on 10 April.
Proven and probable reserve estimates were revised to 18.8 million carats as of 31 January, with the Misery Main zone accounting for 12.3 million carats alone. Indicated and inferred resources were 19.3 million carats.
The scoping sessions for the Jay project located within the Buffer Zone JV property were held in January.