Process route selection is driven by ore mineralogy, grade, liberation characteristics, and target product. KDMine follows a structured process: (1) Ore characterisation — QEMSCAN/MLA mineralogical analysis to identify mineral associations and liberation size. (2) Metallurgical testwork — bench-scale flotation, leach, or gravity tests to establish recovery vs. grade curves. (3) Flowsheet options study — typically 3 options evaluated at scoping level with NPV/CAPEX trade-off. (4) Pilot plant — for complex ores or novel flowsheets, pilot-scale testing (500 kg to 5 t/day) to de-risk the design. (5) Definitive flowsheet selection — based on testwork results, CAPEX/OPEX, and product marketability. KDMine has a network of accredited metallurgical laboratories for testwork management.

A Pre-Feasibility Study (PFS) is an AACE Class 4 study (accuracy −30%/+50%) that confirms technical viability and provides a basis for the investment decision to proceed to full FS. For process plant design, a PFS includes: preliminary mass balance, equipment list with factored sizing, preliminary P&IDs, and a factored CAPEX estimate based on vendor budgetary quotes and factored costs. A Feasibility Study (FS) is an AACE Class 3 study (accuracy −15%/+25%) that provides the definitive basis for a Final Investment Decision (FID). It includes: detailed mass balance (METSIM/JKSimMet), equipment datasheets with vendor quotes, approved-for-design P&IDs, general arrangement drawings, and a definitive CAPEX estimate. The FS is typically required by lenders and boards before committing project capital. KDMine delivers both PFS and FS to international standards.

Typical timelines for KDMine process plant studies: Scoping/Conceptual (AACE Class 5): 4–8 weeks. Pre-Feasibility Study (AACE Class 4): 4–6 months, depending on metallurgical testwork availability. Feasibility Study (AACE Class 3): 9–18 months, including metallurgical testwork (3–6 months), detailed engineering (4–8 months), and CAPEX estimation (2–3 months). Detailed Engineering (AACE Class 1–2): 12–24 months for a typical 5–10 Mtpa plant. The critical path is usually metallurgical testwork — KDMine recommends initiating testwork programmes at least 6 months before the FS start date to avoid schedule delays.

High Pressure Acid Leach (HPAL) is a hydrometallurgical process that uses sulphuric acid at high temperature (250°C) and pressure (50 bar) in titanium-lined autoclaves to dissolve nickel and cobalt from laterite ores. HPAL is the preferred route when: (1) The ore is a limonite-dominated laterite (high Fe, low Mg) — HPAL achieves 95%+ Ni and Co recovery from limonite. (2) The target product is battery-grade NiSO₄/CoSO₄ — HPAL produces a clean mixed hydroxide precipitate (MHP) suitable for battery precursor. (3) The saprolite content is low — high saprolite increases acid consumption and OPEX. HPAL is capital-intensive ($2,000–3,500/t Ni CAPEX) and technically complex, but produces the highest-value battery-grade products. KDMine has designed HPAL plants in Indonesia, Philippines, and Papua New Guinea.

KDMine's commissioning support follows a structured 5-phase approach: (1) Pre-commissioning — mechanical completion checks, instrument loop checks, vendor FAT (Factory Acceptance Testing), and development of commissioning procedures. (2) Cold commissioning — water flushing, pump testing, conveyor running, and instrument calibration without process material. (3) Hot commissioning — introduction of ore/reagents, circuit stabilisation, and initial performance testing. (4) Performance testing — 72-hour or 30-day performance test runs to demonstrate design throughput, recovery, and product quality against contract guarantees. (5) Optimisation — post-commissioning optimisation of reagent dosing, grind size, and circuit configuration to maximise recovery and throughput. KDMine provides resident commissioning engineers on-site for the full hot commissioning period.