Timah, the world's second largest refined tin producer, was responding to a Reuters report on Tuesday on how miners on the Indonesian island of Bangka are moving their mining activities offshore as reserves on land thinned.

Environmentalists have been worried about the impact of sea mining on the island's mangrove area while fishermen said their catches had significantly dwindled due to the sea mining.

"PT Timah is committed to implementing sustainable environmental responsibility in every line of its business, both in environmental and social contexts," it said in a statement.

It said that commitment applied from the initial operational stage to the post-mining reclamation stage.

Timah said since 2016 it had installed 3,105 units of fish shelters and 1,475 units of coral transplant in seas surrounding Bangka-Belitung province.

This year, the company plans to install an additional 1,920 units of fish shelter and aims to release 20,000 squid chicks to help repopulate the waters where it operates.

Tin deposits in the mining hub of Bangka-Belitung have been heavily exploited on land, leaving parts of the islands off the southeast coast of Sumatra island resembling a lunar landscape with vast craters and highly acidic, turquoise lakes.

In some places, restored mining land were often re-dug by unlicensed miners seeking remaining deposits.

Timah said it continues its efforts to restore former mining area into conservation area or eco-tourism centres, among other public facilities.

(Reporting by Fransiska Nangoy; Editing by Martin Petty)