A New Chapter in Downstreaming: AMMAN’s "Smart" Smelter in West Sumbawa
Sun 23 Aug 2026, 16:43 PM
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Mineral downstreaming in West Nusa Tenggara (NTB) province has entered a new phase. PT Amman Mineral Internasional Tbk (AMMAN)’s integrated copper smelter is now moving toward long-term operations after all construction and commissioning work has been completed.
The milestone was marked by the signing of the Completion and Project Acceptance Certificate (PAC) between AMMAN and China Nonferrous Metal Industry's Foreign Engineering and Construction Co., Ltd. (NFC) in Beijing on July 18, 2026. The PAC confirms that the facility has passed performance guarantee tests in accordance with the contract requirements.
The refining complex in West Sumbawa Regency (KSB) processes concentrate into value-added products domestically. The process is supported by an integrated energy system and digital power controls.
The development of the facility has also been monitored by the NTB provincial government. Previously, Head of the NTB Investment and One-Stop Integrated Services Agency (DPMPTSP) Irnadi Kusuma led oversight, monitoring and evaluation of the operations of PT Amman Mineral Nusa Tenggara (AMNT) and PT Amman Mineral Industri (AMIN).
Irnadi Kusuma said the visit was a strategic step by the regional government to ensure that the mineral processing industry complies with regulations. The monitoring also supports the downstreaming targets being pursued in NTB.
“The regional government sees that this industrial area has significant potential to foster various downstream industries that will further strengthen the mineral downstreaming value chain,” Irnadi said recently.
The team also inspected part of AMMAN’s mineral processing and smelter facilities located within the KSB Industrial Estate. The regional government considers the industrial estate to offer opportunities for the development of downstream industries. One of the plans is to build a fertilizer plant using sulfuric acid as its primary raw material. The supply could come directly from the smelter.
The plan shows that downstreaming in West Sumbawa does not stop at mineral refining. Instead, opportunities to develop downstream industries begin with the smelter’s ability to operate according to its design specifications.
1. PAC marks smelter’s transition to long-term operations
Smelter construction does not end once the buildings and equipment are in place. The facility must undergo commissioning, finalization, and testing of production capacity, product quality and technical performance.
AMMAN entered the commissioning phase in 2024. Equipment was tested, furnaces were heated, concentrate was fed into the facility, and the production system was brought online gradually. President Joko Widodo inaugurated AMMAN’s smelter and precious metals refining facilities on September 23, 2024.
The facility then underwent a ramp-up phase and stabilization. Adjustments continued to ensure safe and stable operations and enable the facility to achieve its design performance. The smelter had already been operating for more than a year before the PAC was signed.
The PAC carries a different significance from the physical inauguration. The document marks the completion of construction and the commissioning punch list. A punch list is a list of outstanding work, repairs or improvements that must be completed before a project can be formally accepted. The smelter has also passed its performance guarantee test. The completion of the project is now evidenced by its ability to meet the contractual specifications.
“The completion of this smelter project is an important achievement for AMMAN. Behind it are the hard work, resilience and strong collaboration of all our employees and partners in overcoming various challenges during the construction and commissioning process,” AMMAN President Director Arief Sidarto said in a press statement received on Monday (July 27, 2026).
AMMAN’s smelter is designated a National Strategic Project. The facility is designed to process 900,000 metric tons of concentrate annually. Its feedstock comes from the Batu Hijau mine. The smelter has also been prepared to process ore from the Elang mine in the future.
The integrated processing operation produces copper cathodes, gold, silver, sulfuric acid and selenium. The concentrate does not remain a mining product but is processed at the refining facility into higher-value commodities.
2. Energy and digital control systems support smelter operations
Smelter operations require a stable electricity supply. AMMAN has designed a portfolio combining conventional energy, lower-emission energy and renewable energy.
AMMAN Vice President of Corporate Communications Kartika Octaviana said the company’s energy approach is integrated and designed for the long term. The system is designed to adapt to technological developments, operational needs and sustainability targets.
“We have built an ecosystem connecting Liquefied Natural Gas (LNG), a Gas and Steam Power Plant (PLTGU), and solar power to support the entire operating chain, from mining to the smelter. This approach enables us to provide a more reliable, efficient and lower-emission energy supply compared with conventional mining practices,” Kartika told IDN Times on Saturday (Aug. 1, 2026).
The success of the energy transition is measured through reductions in greenhouse gas emissions, improvements in energy efficiency and supply reliability. AMMAN is not locking its strategy into a single technology. The company continues to assess various energy sources based on operational needs, technological developments, economic considerations and sustainability objectives. This approach leaves room for the integration of new technologies in the future.
AMMAN is finalizing a 450-megawatt Gas and Steam Power Plant, or Combined Cycle Power Plant (CCPP). Under its integrated scheme, LNG from the Benete Bay LNG Terminal will serve as fuel for the CCPP. The electricity will supply the smelter, precious metals refinery (PMR), processing facility expansion and the Batu Hijau mine.
The CCPP uses SGT-800 gas turbines. AMMAN estimates that the combined-cycle efficiency of the technology can reach around 57% to 59%. By comparison, the efficiency of other conventional power plants ranges from 28% to 33%.
Solar power is another component of the portfolio. AMMAN operates a 26.8-MWp solar power plant. Throughout 2025, the solar plant generated 36,629 MWh of renewable electricity. This output was equivalent to avoiding 34,794 tons of CO₂e emissions.
The figure was still below the target of reducing emissions by around 40,000 tons of CO₂ per year. AMMAN explained that lower solar radiation throughout 2025 affected total electricity generation. In the same year, renewable energy accounted for around 13% of the company’s total energy consumption, relatively in line with the previous year.
The “smart” element is also present in electricity transmission and distribution monitoring. AMMAN uses Supervisory Control and Data Acquisition (SCADA) to control the power system in real time while providing operational data.
The Intelligent Load Shedding (ILS) system uses artificial intelligence to manage loads during disruptions or changes. Adjustments can be made without manual intervention. AMMAN’s digital monitoring also covers load planning, generation planning, energy consumption and integrated process control.
Operational data is analyzed to optimize equipment performance and identify efficiency opportunities. The “smart” system operates across the energy network to ensure a reliable electricity supply for the downstreaming facilities.
3. Smelter downstreaming strengthens local human resources
With the smelter in operation, AMMAN’s business chain in West Sumbawa encompasses mineral mining, smelting and refining. Copper cathodes, gold, silver, sulfuric acid and selenium are projected to support the renewable energy, electric vehicle and high-tech manufacturing industries. This allows mineral value-added processing to take place in Indonesia.
“The operation of this smelter reaffirms our commitment to supporting the national downstreaming agenda. Going forward, we hope the policy ecosystem supporting the competitiveness of the domestic processing and mining industries can continue to be strengthened so that Indonesia can maximize the benefits of downstreaming while remaining competitive amid global dynamics,” Arief said.
The transformation also requires a prepared workforce. AMMAN recruits participants in its Graduate Development Program (GDP) and Skill Development Program (SDP) from West Nusa Tenggara. They are directly involved in the company’s energy transition across its operations.
Skills development is carried out through training, certification and development programs tailored to industry needs. AMMAN links the energy transition with the recruitment and development of local workers at its power plants and throughout the energy chain in its operating areas.
Following the signing of the PAC, the measure of the smelter’s success has shifted. The challenge is no longer completing construction, but keeping the facility operating safely, stably and efficiently at its design capacity over the long term. In West Sumbawa, the downstreaming phase is now supported by mineral refining, an integrated energy system and data-based power controls.
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