The indefinite labour action involves 56 unions, which are protesting a government’s proposed reform they see as "anti-workers".
Grupo Mexico Mining News
World number five producer adding 600,000 annual tonnes in six years.
The new section of the Toquepala open-pit mine in southern Tacna, Peru, is expected to begin operations in early 2018.
Mexico’s biggest copper producer is leveraging its relatively low debt and strong profit margins to invest more than $4.6 billion expanding some of its mines.
China is currently the top investor in the country's sector, pumping $19.2 billion into several copper, gold and silver projects.
The former president says lack of immediate benefits for communities has driven mining opposition causing the country to lose billions worth of gold and copper projects.
Six people have been killed in anti-mining protests so far this year, including three at last week's clash between police and locals near Las Bambas copper mine.
The company could extend a 60-day pause in effect since late May to allow locals more time to clear up their doubts about the project’s environmental impact.
The move suspends civil liberties, allowing police and troops to enforce curfews in an effort to end two months of fresh violence in Arequipa.
Farmers, anti-mining activists and local leaders have opposed the project for years, claiming it will pollute key waterways for Arequipa, where the mine will be built.
The expansion will boost the capacity of the Peruvian mine's copper concentrator to 120,000 tonnes per day from 60,000.
Minister of the Environment Manuel Pulgar-Vidal said the debated and long-delayed copper mine won’t hurt water supplies as opponents claim.
The contract has been awarded to a consortium headed by Grupo Mexico, the same company responsible of a major toxic spill in Sonora last year.
Figure is based on preliminary assessments of the damage caused to water, flora, fauna, and wildlife, as well as official information on water quality.
The news represents a relief for local authorities, which have seen several projects halted in recent months.
So far Grupo Mexico has been charged with more than $3 million in fines, and could face more.
Mexico's environmental prosecutor has imposed a new partial order of closure on Grupo Mexico’s Buenavista copper mine.
Around 15,000 of the total 55,000 licences in effect risk fines and even losing all privileges over the land.
Chinese backers are now behind one-third of all Peru’s new mining investments by value.
Authorities said Grupo Mexico lied about a spill of 40,000 cubic meters of acids and heavy metals that contaminated two rivers and a dam in the northern state of Sonora.
Grupo Mexico has denied reports claiming it did not immediately report a massive acid spill from its Buenavista mine in the country's north.
While Canada and the U.S. look at Mount Polley disaster's aftermath, another big spill has contaminated rivers a bit further south.
The mine is expected to produce 120,000 tons of copper a year during its 20 years of mine life.
The South American nation lost the title to China in 2012.
Combined estimate investment exceeds $13 billion, says the government.