Coal miners work inside the mine "La Escondida" (The hidden one) in Villablino, Spain, December 27, 2018. Picture taken December 27, 2018. REUTERS/Eloy Alonso

SANTIAGO, Dec 11 (Reuters) - Chile's mining investment is expected to reach $104.549 billion from this year through 2034, state-run agency Cochilco said on Thursday, up 26% from last year's forecast.

Chile is the world's largest producer of copper and second-largest of lithium, a key ingredient of rechargeable batteries.

* The increase represents the highest investment forecastsince the 2016-2025 period. * New investment includes an expansion at BHP's Escondida,the world's biggest copper mine, and new concentrators atCollahuasi, a copper mine jointly owned by Anglo American andGlencore. * The 2024–2033 investment portfolio was estimated at$83.181 billion. * "In this portfolio, we are seeing how new copper andlithium projects are consolidating as drivers of futuredevelopment," Mining Minister Aurora Williams said in apresentation of the Cochilco report.

(Reporting by Fabian Cambero, Writing by Daina Beth Solomon; Editing by Gabriel Araujo and Aida Pelaez-Fernandez)