Mineral Processing Overview
At the Processing Plant, a hydrometallurgical processing flowsheet will be employed to leach nickel from the Project ores using traditional HPAL (high-pressure acid leaching - the process used to recover nickel and cobalt separately from each other, from low-grade nickel oxide laterite ores). The nickel eluate is processed via solvent extraction (SX) before the final nickel sulphate and cobalt sulphate products are crystallized, dried, packaged, and shipped to the market. Scandium oxide will be generated as a by-product, with scandium extracted from the nickel and cobalt eluate using continuous liquid ion exchange (cLX) before scandium refining and final calcination. High-purity hydrated nickel and cobalt sulphate products, as well as a 99.9% Sc2O3 product, will be produced in the process plant.
The Mining Process
High-Pressure Acid Leach
For the distinct high-quality nickel sulphate and cobalt sulphate products, the Project has chosen high-pressure acid leaching (HPAL) and continuous resin-in-pulp (cRIP), as well as downstream impurity elimination, solvent extraction, and crystallization as the processing approach.
The HPAL process for extracting nickel and cobalt from lateritic ores has a high level of confidence in its robustness. The HPAL processing technology is now in its fourth iteration, and the expertise acquired from its use in functioning plants has greatly improved it. Although commissioning and ramping up HPAL operations is difficult, these difficulties are well studied. In the two prior feasibility studies on the Project, metallurgical testing was commonly performed on nickel, cobalt, and scandium. All previous test work reveals that the Project ore has high nickel extractions of approximately 94 %, while cobalt and scandium extraction utilizing the HPAL method varies from 80 % to 90 % and is occasionally higher.
Metallurgical Test Work Summary
Specialists undertook extensive metallurgical piloting on the extraction and recovery of nickel and cobalt, which included variability testing of over 100 composites of various ore lithologies. This work has provided a solid foundation for the nickel Halmahera Project's design criteria to be established. Nickel was the primary focus of each of these test work programs, but cobalt and scandium were also examined. This research establishes a high level of confidence in metal extraction utilizing the HPAL process and the unit process design requirements that follow. Basic tests were carried out in addition to this earlier work to confirm the results of previous metallurgical test work.
Our latest metallurgical research and development efforts have been centered on:
Ore reserves are rich in all the key metals (nickel, copper, platinum, and palladium) backed by a low cash cost of nickel production compared to peers.Read more
Focus on Tier I assets and new investment management system.Read more
Halmahera Resources has demonstrated financial sustainability throughout the cycle: high profitability.Read more
A solid operating platform in leading mining jurisdictions.Read more
Hydrated Nickel and Cobalt Sulphates
The processing facility is also capable of producing hydrated nickel sulphate (NiSO4.6H2O) and hydrated cobalt sulphate (CoSO4.7H2O) products of high purity. A high-concentration nickel and cobalt sulphate solution with negligible contaminants are produced by the cRIP plant's desorption circuit. As a result, the technique is well suited to the lithium-ion (Li-ion) battery industry, which requires sulphates for precursor manufacture, and it has the potential to reduce process steps now used in the cathode supply chain. In addition, the Halmahera Project will create the following items:
Water Supply and Recycling
The Project's borefield 15 km northeast of the mine, which is licensed for a 2.2 GL/annum abstraction rate, will supply the majority of the raw water needs. This amount covers potable water, fire water, high-pressure hose-down water, mine utility water, and plant water for use in the process, as well as feed to the high-purity water treatment plant for steam production. When there is an abundance of bore water, seawater will be used to complement it. Water from the Tailings Storage Facility will be recycled, and water loss will be avoided by installing fin-fan coolers for the sulphuric acid plant, steam generators, crystallizers, and general plant cooling water.
Environmental and Social
We conducted a number of new surveys with our partners, including over 60 professionals from various disciplines, as part of ongoing projects, including:
The following are some of the most important environmental research findings: