31 July 2025
Harita Nickel has solidified its role as a pioneer in Indonesia’s electric vehicle battery materials industry by upholding a strong commitment to sustainable operations. Residual materials from the High Pressure Acid Leaching (HPAL) process are managed in a dedicated and environmentally safe manner, and even reused for operational needs.
Tailing, a byproduct of the extraction process for Nickel (Ni) and Cobalt (Co) from limonite ore, takes the form of slurry—a thick mixture of solid particles and liquid resembling mud. There have been circulating allegations claiming that Harita Nickel pollutes the environment by dumping tailings into the sea, with even more alarming claims that these tailings contain heavy metals and toxic substances.
In reality, Harita Nickel manages tailings from the HPAL process by solidifying them through a Dry Stack Tailings Facility (DSTF). First, the tailings are neutralized to eliminate any toxins resulting from acid leaching. Then, the solid and liquid fractions are separated using a filter press. The liquid portion is further treated in a Wastewater Treatment Plant (WWTP), while the solid fraction (dry tailings), with a moisture content of about 30%, is compacted and placed in former mining areas to ensure ground stability.
This DSTF method of tailings management was first implemented in Indonesia by Harita Nickel. The operational costs are far from cheap. For illustration, with an annual tailings output of 8.6 million tons from the HPAL plant operated by PT Halmahera Persada Lygend (HPL), a total of 300 workers are employed across five divisions: Geotechnical Engineering, Hydrology & Hydrogeology, Tailing Facility Planning, DSTF Earthwork, and Leachate Treatment Plant.
“The biggest challenge is the high rainfall, especially given the open area,” Nanang Koswara, DSTF Earthwork Supervisor, explained.
So what happens to the dry tailing placement areas when it rains, given they are in open spaces? The tailings placement facility is equipped with drainage systems, leachate collection ponds, buttresses (retaining walls), groundwater monitoring wells, and tools to monitor water quality and soil stability.
In areas with high rainfall, maintaining the slope stability of tailings piles is essential, as the dry tailing material is sensitive to water content changes. To ensure that the piles remain stable and safe, the Geotechnical Division team constantly monitors compaction levels, controls the geometry of the piles, and provides recommendations on safe placement zones for tailings.
The geotechnical team conducting soil stability measurements to ensure the ground can support the tailings pile securely.
“In addition, routine daily monitoring by the geotechnical team is conducted to mitigate potential landslide risks early on. We are committed to ensuring that dry tail placement operations remain safe and smooth,” said Agus Budi Prastyo, Instrument & Geotechnical Supervisor.
While heavy rainfall can benefit the nickel laterite formation process, it also demands special handling of runoff and groundwater—especially in dry tailing storage areas. Improper handling can lead to landslides and environmental contamination.
This is where the Hydrology & Hydrogeology team plays a key role—ensuring runoff water is managed properly and does not interfere with tailings placement activities. Despite high rainfall, operations continue safely and remain free from pollution risks.
“Water quality monitoring is conducted daily at both the inlet and outlet. The testing includes metal content, in situ parameters, and laboratory tests by an external lab,” explained Rahma Maulida, Laboratory Assistant Engineer of the Leachate Treatment Plant Division.
The Leachate Treatment Plant team monitors water in the leachate treatment pond to ensure it meets environmental quality standards before discharge.
Amid the 24-hour operations and the high-risk potential, particularly regarding environmental contamination, there’s something else that keeps the DSTF team united.
“What makes us stay is the sense of family we’ve built. For example, after work we often eat together at the canteen,” shared Rahma.
Leadership that fosters trust is also key. "We are given the space and responsibility here," Agus concluded.
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