Jakarta. Suparta, the former CEO of tin miner Refined Bangka Tin (RBT), died on Monday while serving an eight-year prison sentence for corruption.

He passed away while receiving treatment at Cibinong Municipal Hospital in West Java.

“We still have no information about the exact cause of death,” Attorney General’s Office spokesman Harli Siregar said.

At the time of his death, Suparta was appealing his conviction to the Supreme Court.

In December, the Central Jakarta District Court found Suparta guilty of involvement in illegal tin trade and unauthorized mining activities on properties owned by state-run tin mining company Timah. He was sentenced to eight years in prison and ordered to pay Rp 4.57 trillion ($282.8 million) in penalties.

His co-defendant, business tycoon Harvey Moeis, received a 6.5-year prison sentence and a Rp 210 billion ($13 million) fine. Another RBT executive, Reza Andriansyah, was sentenced to five years in prison and fined Rp 750 million ($46,419).

Prosecutors allege that the conspiracy led to an estimated Rp 300 trillion ($18.5 billion) in damages, largely due to severe environmental destruction.

According to the Financial and Development Supervisory Agency (BPKP), the estimated losses include Rp 271.1 trillion in environmental damages from illegal mining activities, Rp 26.5 trillion in potential revenue losses for Timah, and Rp 2.3 trillion in financial losses linked to smelting operations.

Court documents revealed that RBT played a central role in the illegal tin mining and trade scandal, with access to Timah’s management reportedly facilitated by Harvey. Several Timah executives and officials from the Energy and Mineral Resources Ministry are also implicated in the case.