Official news service Xinhua said the Asian country wants to ensure zero growth of capacity in 2018.
Buenaventura reported lower precious metals, copper and zinc production last year, while Hudbay Minerals reached agreements for landholdings around its Constancia copper mine.
Companies with gold, silver and lithium projects in Brazil and Mexico report financing updates and a CEO appointment.
The growing project pipeline drives forecasts for power and water use in Chile's copper mining industry.
Brazil's CSN is the largest of Usiminas' minority shareholders and raised its stake in its rival through a string of acquisitions in 2011 and 2012.
The US company expects production to fall in 2018 reflecting the sale of its San Bartolomé silver mine in Bolivia and slightly lower output after a bumper 2017 at Palmarejo in Mexico.