The volume of water behind the dam has been rising and concerns had been raised in recent weeks about what could happen as snow melts and its capacity is exceeded.
The miner expects to lower production costs to $1.08 per pound during the 2017 financial year, from a projected $1.21 per pound in the year ending June 2016.
World's five largest mining companies together have lost an astonishing $570 billion in market value since 2011–the worst period of performance since 1966.
Iran is opening $29 billion of projects to foreign investors once sanctions are lifted – acquiring new mining equipment and technology is a top priority.
When the instinct is strongest to curl up in a ball and wait out the ravages of the down market is also when smart companies snap up distressed projects and get to work while capital costs are low.
