SANTIAGO, Jan 25 (Reuters) - Chile's state-owned Codelco , the world's largest copper miner, said on Thursday it had received environmental approvals for a revised plan to extend the working life of its century-old El Teniente copper mine.
The approvals will allow the company to modify its original expansion plan, already permitted and now 44 percent complete, which seeks to add another, deeper level at the mine to access the company's top producing deposit.
The El Teniente project, part of an ambitious, $22 billion multi-year investment drive at Codelco to open new projects and revamp older ones, has been repeatedly delayed by geo-technical issues, the company said in a statement.
Under the revised plans, Codelco will gradually work its way deeper into the deposit in steps, El Teniente General Manager Andre Sougarret said in the statement.
"We've improved the safety of the operation, preserved its profitability and given ourselves the time to continue to reach the deepest parts of the mine, which are much more complex," he said.
Like many copper mines in Chile, El Teniente has suffered from years of declining ore grades.
The expansion will allow Codelco to maintain total output at approximately 450,000 tonnes of refined copper per year.
The expansion project is expected to add 50 years to the life of the mine and is slated to be completed in 2023.
(Reporting by Dave Sherwood; editing by Andrew Hay)