Both companies have been partners in the Veladero mine in Argentina.

The miner and the First Nation want to make sure the development of the gold project is mutually beneficial.

The mine would produce an average of 306,000 gold-equivalent oz. annually at all-in sustaining costs of $757 per oz.

Shares in Rio Tinto are down 4.8% so far this year. Stock in BHP is down 9.6%.

Rio owns 60% of the Diavik mine in Northwest Territories.

The miner wrote to Canadian ambassador Graeme Clark and is hoping to set up a meeting with Lopez Obrador.

Combining statistical methods with machine learning can predict various types of mineral resources based on regional geochemical survey data.

PwC forecasts that miners will take a hit to EBITDA of approximately 6% in 2020.