Chile's state copper producer Codelco has revised its 2012-16 investment plan by US$8bn to US$27bn, the company said in its 2011 annual report.
Last year, Codelco had set a US$19bn figure for its investment portfolio.
The increase is mainly due to a rise in costs for its six so-called structural projects, according to local paper La Tercera.
"The differences between both figures is basically due to an almost US$5bn increase in the structural projects... the increase in mining projects' costs is a phenomenon that is affecting the entire industry," company sources were cited as saying.
The cost increase is mainly attributable to projects in the prefeasibility or feasibility stages. The Chuquicamata underground project was revised up to US$3.7bn while the Radomiro Tomic phase II sulfide project will now require an estimated US$4.7-5bn. The budget for the San Antonio oxide project also increased. "In the case of the latter two, thanks to new studies, production has also increased," Codelco said.
Codelco's biggest investment is Andina phase II which will now cost US$6.4bn. The project is in the feasibility stage and is expected to be resubmitted to the environment ministry's evaluation service around mid-year.
Of the six structural projects that Codelco is developing, only two - Ministro Hales (US$2.5bn) and the new mine level at El Teniente (US$3.1bn) - have investments approved and are in the construction phase.
The other four projects will go ahead, despite the rise in costs. "Even with the increase in costs, the projects are profitable, considering medium and long-term price projections," Codelco said.
In 2012, Codelco will invest a record US$4.3bn.
If Codelco's structural projects are not developed, output could drop to around 800,000t/y of fine copper by 2020. Codelco - the world's largest copper producer - put out 1.74Mt/y in 2011.
Ministro Hales will add 160,000t/y when it starts operating in 2013, the El Teniente new mine level will contribute 415,000t/y from 2017 and Chuquicamata underground will add 343,000t/y from 2018, according to the company's latest update.
Radomiro Tomic is forecast to produce 345,000t/y from 2016, while Andina phase II will add 306,400t/y to current production from 2020. The San Antonio project will add 60,000t/y from 2015.