RAPAPORT... Star Diamond Corporation has started legal proceedings against Rio Tinto, accusing the mining giant of failing to comply with the terms of a joint-venture agreement.In 2017, Rio Tinto closed a deal with the Canadian miner, giving it the right to acquire shares in the Star-Orion South exploration project in Saskatchewan. In November, five years earlier than its original deadline, Rio Tinto gave Star Diamond notice it wanted to purchase a 60% stake in the site.However, a review by a special committee at Star Diamond, together with independent legal counsel, found that Rio Tinto had not complied with all the terms of the agreement, Star Diamond said last month. "Star Diamonds is committed to...enforcing all of [its] rights under the agreement," the company explained at the time, noting it intended to reach a resolution, either through the courts or by a "negotiated solution."Star Diamond has filed suit in the Court of the Queen's Bench for Saskatchewan, it reported last week."Rio Tinto will be strongly defending the legal proceedings on the basis that we have validly exercised the options," a Rio Tinto spokesperson told Rapaport News Monday.Image: The Star-Orion South exploration project. (Star Diamond)