Rio Tinto unveils new tech for bulk sample at Star

Rio Tinto (NYSE: RIO; LSE: RIO) has completed its 2019 bulk sampling program at Star Diamond’s (TSX: DIAM) Star-Orion South diamond project, 60 km east of Prince Albert, in central Saskatchewan.

Using novel technology – a trench cutter sampling rig normally used in civil engineering projects that has been adapted for use at the project – the company has collected 8,271 wet tonnes of material. Each trench took between 9 to 17 days to complete, and reached a depth of up to 251.1 metres.

George Read, Star Diamond’s senior vice-president exploration and development, says that the new sampling technology has the potential to revolutionize future bulk sampling and mining of kimberlites like those at Star-Orion South.

“This ambitious sampling program required significant time to assemble all the components on site, but once it commenced the trench cutter has operated efficiently and successfully, recovering a large bulk sample from the Star kimberlite,” Read said in a release.

An onsite bulk sample processing plant is in the final stages of construction. Once completed, it will be commissioned using kimberlite from Orion South in a 2009 underground bulk sample program. Final diamond recovery will be done off site at a secure facility.

Rio Tinto is earning up to a 60% interest in the project under an agreement signed in 2017. The major will earn its first 51% in Star-Orion South once it completes the first two phases of work: a 10-hole bulk sampling program within the first three years, and then another 10-hole program (or $18.5 million in spending) within the following 18 months.

The Star and Orion-South kimberlites contain global resources of 66 million carats (193 million indicated tonnes grading 15 carats per hundred tonnes and 57 million inferred tonnes grading 11 cpht in Star; and 200 million indicated tonnes grading 14 cpht and 72 million inferred tonnes grading 7 cpht in Orion South).

Although they are very low grade, the kimberlites are known to host high-value, rare, Type IIa diamonds, as well as large stones.

— This article appeared in the November 2019 issue of Diamonds in Canada and was originally published on www.canadianminingjournal.com.