PT Rajawali Corp., an Indonesian conglomerate owned by tycoon Peter Sondakh, is considering selling its controlling interest in gold miner PT Archi Indonesia, according to people with knowledge of the matter.

The Jakarta-based conglomerate is working with a financial adviser on the potential divestment and could decide to keep a stake, said the people, asking not to be identified as the process is private. Rajawali, which owns about 85% of the miner’s shares, is seeking about a $1 billion valuation for the company in a deal, one of the people said.

Archi shares surged as much as 18% in their biggest gain since January in Jakarta on Friday after the Bloomberg News report. The stock has advanced about 15% this year, giving the company a market value of around 9.4 trillion rupiah ($602 million).

Deliberations are ongoing and there is no certainty that the Indonesian conglomerate will proceed with a sale, the people said.

A representative for Archi said they didn’t have information about the deal as it’s a shareholder matter, while a representative for Rajawali didn’t respond to requests for comment through phone and emails.

Founded in 2009, Archi is one of the biggest pure-play gold producers in Indonesia and Southeast Asia, according to its website. The Jakarta-headquartered company owns the Toka Tindung gold mine in North Sulawesi. The asset has produced about 1.9 million ounces of gold as of 2020, supported by 3.6 million tons of processing plant capacity per year, the website shows.

The company’s initial public offering raised about 2.8 trillion rupiah in 2021. The share price has declined by more than half since it began trading.

(Updates Archi shares move in third paragraph.)