Financial markets and gold investors were jittery at the start of the trading day, with the Fed poised to raise interest rates for the second time this year.
Barrick confirmed chairman John Thornton met President John Magufuli for talks Wednesday, but didn't mention the details of what, if anything, had been agreed.
Gemfields, which mines for emeralds and amethysts in Zambia and for rubies in Mozambique, had already received a buyout offer from largest shareholder Pallinghurst Resources.
Canada will need more pipelines built through to 2030 to transport an additional 1.3 million barrels per day of oil sands production to markets across North America and around the world, according to the Canadian Association of Petroleum Producers.