The precious metals gain ground following the recent rout, helped by a softening US dollar and rising oil prices.
Cash-strapped state mining company Comibol was forced to shut down some operations last year in the face of slumping metals prices.
IABr allegedly tried to hurt legally established steel rebar importers in the country.
The shuttered La Oroya polymetallic smelter in Peru's central Andes is too obsolete to be able to produce copper cleanly, meaning potential buyers will only be able to operate the complex's zinc and lead circuits, according to the government.
The stainless steelmaker practically doubled shipments abroad as a proportion of total sales and increased the number of new clients.
The acquisition comes after the board of Usiminas reached a consensus on the "urgent" need to pump cash into the company, which is being buffeted by severe financial headwinds.