Capstone Copper (ASX:CSC) submitted its Mantos Blancos Phase II project to Chile's environmental impact assessment process, moving forward with plans to extend and expand operations at the Antofagasta-based mine, according to a Monday filing with the Australian bourse.

The project will increase sulfide concentrator throughput to at least 27,000 tonnes per day, up from 20,000 tonnes, through the addition of new concentrate filtration, thickening, and tailings filtration systems, as well as upgrades to existing processing facilities, per the filing.

The project also proposes the development of a new in-pit tailings storage facility beyond 2030 to support long-term environmental management and ensure continued operational stability, the filing said.

The company said a pre-feasibility study is planned for the third quarter, with expanded production expected to commence between 2030 and 2031, subject to regulatory approvals and construction timelines, the filing added.