Indonesia's Sumbawa Timur Mining Could Hold Gold Reserves Larger Than Freeport's

The Indonesian Mining Institute (IMI) has revealed that Indonesia’s gold reserve potential remains substantial and is spread across various regions. One exploration-stage mining company is even touted to have gold reserves larger than those of PT Freeport Indonesia in Central Papua. IMI Chairman Irwandy Arif stated that this potential shows Indonesia still has many mining areas that can be developed through exploration activities. The company in question is Sumbawa Timur Mining (STM), which manages the Hu’u Project in Hu’u District, Dompu Regency, West Nusa Tenggara. “The potential is still very large. In West Nusa Tenggara, we know Sumbawa Timur Mining. Its reserves could exceed Freeport’s. And it is on the same belt. We have been able to identify it, even though the belt was already known before,” Irwandy said during the Mindialogue 2026 event in Jakarta on Wednesday. PT Sumbawa Timur Mining, as the holder of a 7th-generation Contract of Work (KK) from 1998, is still conducting gold reserve exploration at the Onto mine in Hu’u District, Dompu Regency, West Nusa Tenggara. Having held the Contract of Work since 1998, the company has been exploring for this treasure trove of gold for 28 years. STM President Director Bede Evans previously explained that the Onto mineral resource potential is part of the Hu’u Project, owned by PT STM under the 7th-generation KK signed with the Indonesian government on 19 February 1998. STM’s shares are majority-owned by Vale S.A. (80%) through Eastern Star Resources Pty Ltd, with the remainder held by PT Aneka Tambang Tbk (20%). “Currently, our engineering team continues to develop various options for how the Hu’u Project can be developed into a mining project in the future,” he told CNBC Indonesia some time ago. According to company data from the last public announcement in 2022 regarding the Onto deposit, indicated mineral resources were recorded at 1.1 billion tonnes, with each tonne containing 0.93% copper and 0.56 grams of gold. Meanwhile, inferred mineral resources were recorded at 0.96 billion tonnes, with each tonne containing 0.87% copper and 0.44 grams of gold. Since exploration began in 2010, the project had cost at least US$200 million up to 2021.