Bhubaneswar, Sep 18 - The state-owned National Aluminium Co Ltd (NALCO) Friday said it had received the central government's approval for mining lease in Andhra Pradesh where it plans to build a 1.4 million tonne greenfield alumina refinery at an estimated investment of Rs.6,000 crore.

'The government of India has accorded prior approval for the mining lease proposals of the government of Andhra Pradesh for awarding lease to NALCO over Gudem and Katamraju Konda bauxite blocks in Andhra Pradesh,' the company said in a release.

Andhra Pradesh had recommended to the central government to grant mining lease to NALCO. The mines are estimated to have 85 million tonnes of bauxite reserves.

Nalco plans to build a 1.