Dairi Prima Mineral Ready to Develop Underground Mine
Mon 27 Jul 2026, 09:01 AM
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PT Dairi Prima Mineral (DPM) is preparing to develop an underground mine to produce zinc (Zn) and lead (Pb). The joint venture between PT Bumi Resources Minerals Tbk (BRMS) and NFC (Hong Kong) Metal Resources Company Limited will develop the Anjing Hitam and Lae Jehe mining prospects in Dairi Regency, North Sumatra.
Dairi Prima Mineral Technical Manager Widianto said the company this year secured final approval for its feasibility study as well as an environmental permit through an addendum to its Environmental Impact Assessment (Amdal). DPM has also obtained a Forest Area Borrow-to-Use Permit (PPKH) covering 53.11 hectares for mining activities, valid through Dec. 29, 2047.
DPM will first develop the Anjing Hitam prospect, which, based on its 2025 estimate, contains mineral resources of 8.53 million tons grading 13.8% zinc and 7.9% lead. Following resource conversion, Anjing Hitam has ore reserves of 7.70 million tons with grades of 12.5% zinc and 7.3% lead.
DPM estimates that developing the Anjing Hitam underground mine and constructing its ore processing plant will require investment of around USD 450 million. The company plans to begin underground mining development and plant construction in the first quarter of 2027.
DPM expects the construction process to take around two years. "God willing, we expect to begin extracting ore from the underground mine in the fourth quarter of 2028. Ore processing is then expected to start in the first quarter of 2029," Widianto said during the Modern Underground Mining Discussion held on Monday (July 27, 2026).
DPM's processing plant is designed to handle 1 million dry tons of ore annually. The ore will contain zinc grades of around 11%-15% and lead grades of between 6%-9%, producing lead concentrate with a grade of 56% and zinc concentrate with a grade of 52%.
Over the life of the operation, DPM estimates it will produce 2.43 million dry tons of concentrate containing 821,150 tons of zinc and 473,895 tons of lead. In addition to zinc and lead concentrates, ore processing will also produce sulfur concentrate.
"The commodities we plan to produce, namely lead and zinc, are classified as critical and strategic minerals. We hope to realize the DPM project," Widianto said.
Zinc and lead are used by various domestic industries, including welding, batteries, and automotive batteries. Sulfur concentrate production also carries strategic value by reducing Indonesia's reliance on imports. Demand for sulfur is expected to rise as more High Pressure Acid Leach (HPAL) facilities begin operating in the country.
Based on current reserve estimates, the Anjing Hitam prospect has a mine life of around nine years. DPM is continuing efforts to increase resources and reserves to extend the mine's operating life. At the same time, the company is preparing to develop the Lae Jehe prospect.
According to its 2025 estimate, Lae Jehe contains mineral resources of 27.90 million tons grading 6.1% zinc and 3.7% lead. Ore reserves are estimated at 10 million tons with grades of 6.4% zinc and 3.8% lead.
"We are still developing the Lae Jehe prospect because its grades remain lower than those at Anjing Hitam, so we are continuing infill drilling. Our goal is to have Lae Jehe ready before Anjing Hitam is depleted, allowing operations to continue seamlessly," Widianto said.
NFC (Hong Kong) Metal Resources Company Limited is the majority shareholder in DPM with a 51% stake, while BRMS holds the remaining 49%.
Permitting and Environmental Aspects
DPM has undergone a lengthy process before reaching the stage of mine development. The project's permitting process has spanned nearly three decades since its Contract of Work was signed in 1998. Exploration activities were conducted between 1997 and 2002, leading to the discovery of the zinc and lead deposit later named the Anjing Hitam prospect.
The first feasibility study was completed in 2004, while the Environmental Impact Assessment (Amdal) was approved by the Dairi Regent in 2005. DPM subsequently obtained a Forest Area Borrow-to-Use Permit (IPPKH) covering 53.11 hectares in 2012 before revising its feasibility study in 2015 following changes to the location of the mine portal, the Tailings Storage Facility (TSF), and the explosives storage facility.
In 2022, the government approved an addendum to the Environmental Impact Assessment accommodating the three changes. However, in 2024, Indonesia's Supreme Court ruled in favor of a community group's lawsuit challenging the approval of the Amdal addendum, prompting the Environment Minister to revoke the approval in 2025 in accordance with the court's ruling.
Based on the latest assessment underpinning the revised feasibility study, DPM has two main prospects: Anjing Hitam and Lae Jehe. Widianto emphasized that the company will meet environmental and sustainability requirements in operating the underground zinc and lead mine.
He explained that DPM will apply a combination of longhole stoping and cut-and-fill mining methods, allowing mined-out voids to be backfilled using processed tailings. The use of tailings as backfill material has received technical approval from the government.
"Tailings will not be disposed of or stored on the surface. Instead, the material will first be separated into liquid and solid components. The liquid will be reused in the processing plant, while the solids will be mixed with cement and pumped back into the underground workings as backfill material," Widianto said.
The cut-and-fill mining method minimizes land disturbance, helping preserve forests and surrounding ecosystems. "The tailings backfill system not only maintains the stability of underground mining areas but also supports environmental protection and compliance with regulations," Widianto said.
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