China Railway Construction Corp. and Tongling Nonferrous Metals Group Holdings Co. announced their all-cash offer for Corriente on Monday in a statement through the Hong Kong stock exchange.

Corriente develops copper, gold, silver and molybdenum mines and its main assets are mining rights in southeastern Ecuador's Corriente Copper Belt, the statement said.

Raymond James base metals analyst Tom Meyer said Corriente was an obvious target because of its world-scale copper projects and the expectation that copper prices will rise.

"Given the recent uptick in commodity prices, we expect an acceleration in M&A activity in the base metals sector," he said in a note.

Minera Penmont -- which is 44% owned by Newmont and controlled by Mexican miner Fresnillo Plc -- on Sunday trumped a revised Christmas Eve offer for Canplats.

"The Minera bid is worth 9% more than the Goldcorp offer and is a "superior proposal," Canplats said in a statement. Shareholders will receive $4.80 in a mixture of cash and shares in a new exploration company.

Canplats is a junior miner whose exploration efforts are based on the Camino Rojo gold and metals project in Mexico.

International Royalty says the deal it has with Royal Gold, made earlier this month, would be worth about $749-million in cash and stock. The rival Franco-Nevada offer is worth about $649-million in cash.

"The Royal Gold transaction is superior to the Franco-Nevada offer and more attractive to IRC shareholders," International Royalty said in a release.