The giant trench cutter rig is one of the technologies being used by Rio Tinto but Star Diamond has issues with its effectiveness. (submitted photo/Rio Tinto)  

By Glenn Hicks

diamond dispute

Star Diamond criticizes Rio Tinto technology at Fort à la Corne diamond project

Nov 20, 2020 | 8:00 AM

The main partners at the Project Falcon diamond exploration site east of Prince Albert continue to argue about the effectiveness of the methods being used to extract and recover the precious stones.

Star Diamond Corp., which owns the rights to explore the diamond-bearing kimberlites at the Fort à la Corne property, claims an internal study shows mining giant Rio Tinto’s methods of extraction and bulk sampling are unproven and are damaging the diamonds while also causing major cost overruns.

Rio Tinto however disagrees with its partner’s conclusions about the exploration technology it is using. It said it remains focused on reviewing the bulk sampling results and is assessing options to progress the project.

The Project Falcon venture, if it leads to an operating mine, has the potential for 700 full time jobs over many decades.

Star Diamond calls methods ineffective

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Star Diamond has previously launched court action against Rio Tinto citing various claims including the mining giant breached their options agreement which would give Rio Tinto a 60 per cent stake in the project, have run up excessive costs, and failed to share information. Rio Tinto denies these allegations. Star Diamond said it would now be adding the findings about the diamond breakage to their Statement of Claim in the ongoing litigation.

In a media release issued Thursday, Star Diamond said, in part, the study showed the processes used by Rio Tinto in their recovery and bulk sampling of the diamonds was causing “undue breakage, resulting in significant unnecessary cost overruns and materially damaging Star Diamond’s interest in the [project].”

Star Diamond claims Rio Tinto’s extraction and diamond recovery methods are excessively expensive and no better than Star Diamond’s methods used up to 16 years ago. (submitted/Star Diamond Corp.)

In essence, the company is claiming results of the first four of the 10 giant trenches that were drilled this year, show fewer larger diamonds than expected have been recovered. Star Diamond contends Rio Tinto’s “unproven and inadequately tested processes” regarding their trench cutting technology and bulk sampling process – which extracts diamonds from the kimberlite ore – are not producing the results they expect.

In the media release, Ken MacNeill, the president and CEO of Star Diamond, called Rio Tinto’s methods “ineffective …in retrieving larger sized diamonds and less diamond breakage,” and said Rio Tinto had purported to expend in excess of $100 million on its bulk sampling program “…but has achieved little more than replicating the historical diamond grade results from Star Diamond’s own underground bulk sampling… [conducted] between 2004 an 2009 at a fraction of the cost.”

paNOW requested an interview with a Star Diamond representative but they were not available for comment.

Rio Tinto defends technology

Rio Tinto responded to paNOW’s request for comment via email. A spokesperson said “Rio Tinto does not agree with Star Diamond’s conclusions on the effectiveness of the sampling methodology and is confident in its ability to defend its use of the trench cutting technology on this project.”

When asked how the situation may impact their 2021 exploration drilling schedule at the Fort à la Corne site, Rio Tinto said it was currently focused on reviewing the results that are being delivered from the bulk sample program and assessing options to progress the Falcon project.

“We expect to provide an update on the work planned for 2021 towards the end of the first quarter,” the company said.

The spokesperson also highlighted comments previously made by a Star Diamond executive in an October, 2019 news release which Rio Tinto says “gives Star Diamond’s view on the new use of trench cutter technology.”

It cited Star Diamond senior VP of exploration and development George Read as saying, in part:

RTEC [Rio Tinto Exploration Canada], have successfully applied this new sampling technology and completed the trench cutter bulk sampling program on the Star Kimberlite. 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…”

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glenn.hicks@jpbg.ca

On Twitter:@princealbertnow