Star Diamond Corp. [DIAM-TSX; SHGDF-OTC] announced that a total of 2,517 diamonds weighing 120.1 carats have been recovered from the first bulk sample trench (19FALCT001) excavated on the Star Kimberlite at the Fort à la Corne kimberlite field in central Saskatchewan.
These results are from the first of 10 bulk sample trenches that were excavated by 60% optionee Rio Tinto Exploration Canada Inc. in 2019. The average diamond grade from this first trench is similar to historical diamond grade results detected from the underground bulk sampling and large diameter drilling completed on the Star Kimberlite between 2004 and 2009. These results are also similar to the overall weighted average grade (14 cpht) reported in Star Diamond’s Preliminary Economic Assessment of the Star and Orion South kimberlites. The three largest diamonds recovered are 3.27, 3.03 and 1.73 carats, respectively, and were all recovered from Early Joli Fou (EJF) kimberlite. The EJF is the dominant kimberlite unit within the project in terms of ore volume and diamond grade.
As further referenced below, there are indications that recent diamond breakage has occurred in the diamond parcels recovered from 19FALCT001, suggesting that the extraction and/or processing systems being used by RTEC may be resulting in diamond breakage. Comprehensive diamond breakage studies will be required to assess the nature and extent of the diamond breakage resulting from Rio Tinto’s methods and the possibility that larger diamonds would have been recovered absent such breakage.
Senior Vice President Exploration and Development, George Read, states: “The diamond results from 19FALCT001 provide an early assessment that the trench cutter bulk sampling method has the potential to replicate grades similar to the previous underground bulk sampling and LDD performed by Star Diamond on the Star Kimberlite. Individual EJF kimberlite samples in this first trench exhibit a range of grades (4.88 to 23.34 cpht), which are as expected for the EJF kimberlite.”
To date, kimberlite material from four trenches (19FALCT001, 19FALCT00, 19FALCT003 and 19FALCT010) has been processed by Rio Tinto through the on-site Bulk Sample Plant, with concentrates forwarded to the Saskatchewan Research Council for final diamond recovery and reporting. Currently, only the diamond results for the first trench have been fully reported to Star Diamond by the SRC.