Private equity firm Waterton Global Resource Management, which now owns about 7 percent of Hudbay, called meeting after the Canadian base and precious metals refused a proposal for board changes.
The government has introduced new regulations to ban asbestos and products containing asbestos, but they don't apply to residues left from mining the carcinogenic material.
The company is also seeking direct talks with the country's government, as it's been excluded so far from negotiations between controlling shareholder, Barrick Gold, and President John Magufuli.
Decision comes after the companies received Wednesday a preliminary geological assessment of the property, which shows Heritage contains several targets for modern alluvial diamond placer deposits.
The Rajo Inca project would convert the existing asset, which has been in operation since 1959 and is due to run out of ore in 2021, to an open pit mine from an underground one.
