Chinese officials have allowed commodities giant Glencore plc to take its final step in a $35 billion acquisition of miner Xstrata—the biggest of its kind—after agreeing to sell a $5.2 billion project to ease the Swiss company’s grip on copper.

Xstrata’s Las Bambas mine in Peru had been expected to be given guidance to satisfy Ministry of Commerce officials and antitrust authorities; Glencore, however, also pledged commitments to supply copper, zinc and lead to the mainland through 2021.

Glencore had already noted that Chinese officials were concerned about its dominance of global copper concentrate; both Glencore and Xstrata combined account for 7% of global copper. Glencore will now start the process of selling Las Bambas—expected to produce an annual 400,000 metric tons (mt) of copper—in Q2 2013 with the goal of finding a buyer by August 2014. In satisfying China’s concentrate demand, meanwhile, Glencore agreed to supply 900,000 mt of copper to Chinese clients annually until 2021.