Water

Water conservation is an integral component of sustainable mining. The management, usage, and monitoring of water quality in every operation and project of the Merdeka Copper Gold are conducted taking into account global environmental threats, local environmental conditions, and surrounding communities.

Merdeka’s commitment to water conservation is reflected in our Sustainability Policy. We consistently comply with government efforts to preserve water resources, as outlined in Article 24 of Law No. 17 of 2019 on Water Resources. To fulfill this commitment, Merdeka implements a water management strategy that focuses on three key points:

Reducing the extraction of raw water from natural sources, particularly groundwater and surface water.
Maximizing the use of circulated and recycled water for operational needs.
Ensuring that the quality of water discharged into public water bodies meets the required standards and regulations.

Through consultations with various stakeholders, we responsibly utilize water resources with efficiency in mind. This is especially crucial considering that the Tujuh Bukit Gold Mine (Banyuwangi, East Java) and the Wetar Copper Mine (Wetar Island, Southwest Maluku) are located in areas considered a top priority in climate resilience studies related to water conducted by the Ministry of National Development Planning/National Development Planning Agency in collaboration with Low Carbon Development Indonesia. The designation of these areas as top priority mandates the Tujuh Bukit Gold Mine and Wetar Copper Mine to conduct water balance studies to ensure an adequate water supply for mining operations, the environment, and local communities.

The Tujuh Bukit Gold Mine and Wetar Copper Mine employ a Closed Loop Water System, which recycles water for operational needs, sourcing water only from within the operational area, and ensuring that the quality of water discharged into public water bodies meets the required standards and regulations.

Water Management at Tujuh Bukit Gold Mine in 2022

Discharged 7,260 megaliters of water.
Withdrew 102.6 megaliters of rainwater and 36.4 megaliters of groundwater.
Recycled 702 megaliters of water from detoxified water for ore processing and supporting activities, accounting for 7% of the total water used.

Water Management at Wetar Copper Mine in 2022
Throughout 2022, BKP-BTR withdrew a total of 262.5 megaliters of water. In the same period, BKP-BTR released 301.5 megaliters of water from mineral processing into the Kuning River and runoff water into the Kuning River (1,938.7 megaliters), Wetuk River (369 megaliters), and Koreng River (540.7 megaliters).

Water Management in the Merdeka Group’s Other Mining Operations and Projects in 2022
In 2022, a total of 12,735.7 megaliters of water were released by Merdeka. Throughout the year, there were no significant incidents of effluent spills in Merdeka’s operational areas that caused disruptions to the environment and surrounding communities.
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Table 1. Water Extractions in Each Merdeka Business Unit in 2022.

Water Management at Tujuh Bukit Gold Mine

The Tujuh Bukit Gold Mine utilizes water from six rainwater catchment dams for operational and domestic purposes, as well as groundwater from three boreholes with Water Extraction Permits (SIPA) for other domestic needs and plant propagation.

These dams are highly effective in capturing rainfall in the mining area, which experiences high rainfall (3,000 mm/year). Dam 6, located upstream, collects rainwater and allows sediment to settle, fulfilling domestic water needs. When Dam 6 reaches capacity, the excess rainwater flows into Dam 5. After sediment settlement in Dam 5, the water is gradually directed to Dam 3, which then flows water to Dam 2 and Dam 1.

Tujuh Bukit Gold Mine has established a compliance point (CP-1) between Dam 1 and Katak River to monitor the flow rate and water quality when it needs to be released into the river. This ensures that the water received by Katak River meets the government’s quality standards. CP-1 compliance point is in accordance with the Liquid Waste Disposal Permit (IPLC) issued by the Environmental Agency (DLH) of Banyuwangi Regency. The water monitoring facility is equipped with an automatic water monitoring device known as SPARING (Continuous and Networked Monitoring System for Wastewater Quality), as mandated by Ministerial Regulation No. P.80/MENLHK/SETJEN/KUM.1/10/2019. The SPARING device is connected to the server of the Ministry of Environment and Forestry (KLHK), allowing direct access to monitoring data on the flow rate and water quality released from Dam 1 to Katak River by KLHK.

Dams 1, 2, 3, 5, and 6 are frequently visited by Javan Pond Heron (Ardeola speciosa) and Great Egret (Egretta alba) for drinking and foraging. During certain seasons, flocks of Lesser Whistling-Ducks (Dendrocygna javanica) also visit the dam area. The presence of these wildlife species indicates that the water in these dams is safe for the environment.

The only dam that functions to collect process water, including runoff rainwater, in the leaching area is Dam 4, also known as the Storm Water Pond (SWP). The water in Dam 4 contains a low concentration of cyanide (a chemical used in the mineral leaching process) and is subsequently recycled or reused for mineral leaching. To prevent bird access, the water surface in Dam 4 is covered with floating bird balls, serving as a barrier. Dam 4 or SWP is constructed with compacted clay soil as the base and dam walls, lined with Linear Low-Density Polyethylene (LLDPE) that is impermeable to prevent process water leakage into the surrounding soil, ensuring environmental safety. In the event of heavy rainfall, excess water from Dam 4 undergoes detoxification treatment before being directed to Dam 3, ensuring its safety before flowing into Dam 2 and Dam 1.

In 2021, Tujuh Bukit Gold Mine added two compliance points. The first is CP-2, located at the sediment settling pond in the mining area, with occasional discharge to Pasir Pendek River during the rainy season. Some of the water collected in the settling pond is also pumped to Dam 3 for operational use or recycling purposes. The second compliance point is CP-3 at the surface facilities of the underground Tujuh Bukit Copper Project, with discharge to Dadapan River. Both CP-2 and CP-3 compliance points comply with the Wastewater Discharge Permit issued by the Banyuwangi Regency Government on January 28, 2021.

Water Management at Wetar Copper Mine

Wetar Copper Mine manages water within a closed circuit system. The managed water comes from mineral processing residues and runoff water. Water from mineral processing residues is collected in Storm Water Ponds (SWP) 3, SWP 2, and KK SWP, utilizing former mining pits. Runoff water is collected in sediment ponds Sump 3, Sump 4, Sump 5, Wetland, and the newly added sediment ponds in 2022: sediment ponds SP-1 and SP-2.

Both runoff and mineral processing residue collection points are connected to several rivers. Sump 3, Wetland, and SWP 3 are connected to the Kuning River; SP-1 and SP-2 are connected to the Lurang River; and Sump 4 and 5 are connected to the Wetuk River and Koreng River, respectively. If it is necessary to release water into the river, the water collected in the sediment ponds is neutralized beforehand to ensure it meets the government’s quality standards when discharged. Each release at the compliance points is measured, monitored, and reported to the government on a quarterly basis.

Wetar Copper Mine also monitors the water quality in the rivers within the mining area and the coastal areas near the river estuaries. River and coastal monitoring is conducted quarterly by a third party, and the results are reported to the government.