Create FREE account or log in

to receive MINING.COM digests

Over 3,000 diamonds recovered from Star-Orion South project in Saskatchewan

Diamonds recovered at the Star-Orion South project. (Image courtesy of Star Diamond).

Star Diamond (TSX: DIAM) announced that 3,534 diamonds weighing 210.68 carats have been recovered to date from the ninth bulk sample trench excavated on the Star kimberlite at the Star-Orion South project in north-central Saskatchewan, Canada.

The project is a joint venture with Rio Tinto Exploration Canada, which undertook the excavation of the ninth trench in 2019.

According to Star Diamond, among the thousands of rocks recovered from the trench, three were large 10.13, 8.10 and 7.29-carat Type IIa diamonds, while 25 diamonds were greater than 1 carat. The latter were all recovered from the Early Joli Fou kimberlite, which is the dominant kimberlite unit within the project in terms of ore volume and diamond grade.

Initial results from the first nine reported trenches continue to validate the grades outlined in Star Diamond’s preliminary economic analysis

“The recent recovery of larger Type IIa diamonds from Rio Tinto Canada’s bulk sample program continues to strengthen our expectation for recovery of large, high-value diamonds in a future producing diamond mine,” Ken MacNeill, Star Diamond CEO said in a media statement.

“There were also 5.15 and 3.44-carat diamonds recovered from the ninth trench, with the 3.44-carat diamond being an ‘H’ (near colourless) octahedron.”

MacNeill also said that initial results from the first nine reported trenches continue to validate the grades outlined in the company’s preliminary economic analysis, which was based upon its own prior underground bulk sampling and large diameter drilling programs.

“Star Diamond has now publicly reported initial results from nine of the 10 bulk sample trenches excavated by Rio Tinto Canada,” the executive said. “Until critically important and comprehensive diamond breakage studies are completed, the processing, diamond recovery and reporting of all diamond results on the bulk sample trenches excavated by Rio Tinto Canada will not be complete.”

Rocky partnership

Located east of Prince Albert, Saskatchewan’s third-largest city, Star-Orion is a large, low-grade project that contains both large diamonds and rare Type IIa stones.

Based on the most recent economic study on the project, Star-Orion has the potential to produce 66 million carats over a 34-year mine life. This would make it the first operational diamond mine in the prairie province. 

But mine development hasn’t run smoothly. The JV partners are engaged in a legal battle over accusations by Star Diamond that RTEC improperly exercised its options to obtain a majority ownership stake in the proposed operation.

In August, a Canadian court ruled that Star Diamond had grounds to take its legal fight with Rio Tinto (ASX, LON, NYSE: RIO) to court, but a trial date has yet to be set.