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

• A sizer and a mill for ore preparation and milling: The larger, lower-grade quartz particles are eliminated before thickening, and the mill discharge is sorted by screening.
• HPAL: Before running into the pressure acid leach autoclaves, slurry from the storage tanks is heated and mixed with concentrated sulphuric acid at high temperature and pressure. The partially neutralized leached slurry is subsequently released from the autoclave through three flash vessels.
• Nickel cRIP: The nickel/cobalt continuous resin-in-pulp adsorption circuit collects nickel, cobalt, and scandium as byproducts, as well as some contaminant metals, from the partially neutralized slurry. The nickel, cobalt, and scandium are eluted from the resin into a high-grade, low-impurity-rich liquor after desorption with dilute sulphuric acid. The depleted slurry is pumped to the tailings stream, where it is neutralized, thickened, and neutralized.
• Refinery and Scandium cLX: The scandium liquid ion-exchange collects scandium from the nickel/cobalt eluate and transports it to the scandium refinery, where it is processed into a high-purity scandium oxide product for sale.
• Purification and recovery of nickel/cobalt sulphate: Following the scandium cLX, the nickel/cobalt eluate is neutralized and processed through solvent extraction for impurity removal, cobalt separation, and nickel separation, followed by ion exchange polishing and crystallization to create high-quality nickel and cobalt sulphates.
• Neutralization and storage of tailings: Tailings will be delivered to the Tailings Storage Facility as a solution with a solubility of approximately 42 % w/w.
• Reagents and utilities for the process (sulphuric acid, steam, water, limestone, other).

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:

• Applying cRIP technology to the Project;
• Demonstrating the abilities to create ultra-pure scandium oxide. Acid consumption of the Project ore has been found to be reasonably low, ranging between 240 and 290 kg/t. This is a considerable benefit for the Project, as acid use accounts for a large amount of the total operating costs. High leach extractions – 95.7 % for nickel and 80 % for cobalt – and better total metal recoveries of 90.3 % have also been demonstrated in HPAL testing.

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:

• Nickel sulphate – mainly used in the lithium-ion battery market;
• Cobalt sulphate – mainly used in the lithium-ion battery market;
• Scandium oxide – a new market, but one with a lot of potential as an alloying ingredient for lightweight aluminum alloys;
• Ammonium sulphate - this will largely be used as a fertilizer in agriculture.

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:

• Environmental Control Plans - the development and implementation of socio-environmental programs;
• Fauna and flora inventories;
• Modeling of air dispersion;
• Water balance and hydrogeological modeling;
• Water grants reports;
• On-site visits by physical, biological, and social analysts;
• Ongoing air, noise, and water monitoring.  Our plan/response to minimize, manage, and mitigate these risks, as well as monitor performance, has identified key environmental and social risks and impacts. This will be done through a specific system, which will be applied before, during, and after construction to ensure compliance with local and international standards.

Environmental

The following are some of the most important environmental research findings:

• Air quality: According to dispersion modeling, main pollutant and dust emissions will be within national and international requirements.
• Greenhouse gas (GHG) emissions and climate risk: GHG emissions for the Project were estimated, and climate hazards were assessed. We have determined that our GHG emissions have a lower impact than those of similar operations in the area, and we have committed to reporting on an annual basis.
• Soil and water quality: The Project has plans in place to prevent soil erosion, sedimentation, and fuel and chemical contamination of soil and water.
• Water: We adjust water abstraction levels in response to seasonal fluctuations in order to keep rivers flowing, especially during the dry season.
• Wastes: The solid waste management strategy will address non-mineral wastes.
• Habitat: The Project will have the greatest impact on open land. We have created a number of biodiversity, flora, and fauna management and monitoring projects.
• Protected areas: The Project will have no impact on any internationally or nationally recognized habitat or species conservation areas.