SANTIAGO, March 8 (Reuters) - Copper production at Chile's top miners closed out January unevenly, with state giant Codelco slipping in the month, according to data released by the Chilean Copper Commission (Cochilco) on Friday.

Codelco, the world's top copper producer, saw its production sink nearly 16% year on year to 107,000 metric tons, Cochilco said.

The state miner has struggled to recoup output as expansion projects meant to make up for a decline in ore quality have been plagued by delays, and

costs are mounting

.

Meanwhile, output at BHP-controlled mine Escondida , the largest copper deposit in the world, grew 4.5% to 97,500 tons in the month.

Collahuasi, a joint venture by Anglo American and Glencore, saw a more marked leap in production, climbing almost 22% to 52,200 tons.

Overall, the nation's output remained largely stable, inching up just 0.51% to 433,800 tons. (Reporting by Natalia Ramos; Editing by Kylie Madry)