SANTIAGO (Reuters) -Chile's Codelco, the world's largest copper producer, on Tuesday posted a pre-tax profit of $606.9 million in the nine months to September, slightly below the $612.2 million reported in the same period last year.

The state-owned miner said its own output totaled 937,000 metric tons, up 2.1% from the same period last year.

The production increase was achieved despite an accident on July 31 at its flagship El Teniente mine - Codelco's most profitable operation - which forced a temporary halt to mining and smelting.

"This unfortunate accident impacted the production results achieved at the end of the second quarter of this year," the company said in a statement.

CEO Ruben Alvarado said that Codelco expects to have more conclusive information about the accident by the end of the year.