This brief checks a widely repeated depletion narrative line by line against public data — what holds, what has the wrong number, and what has no independent evidence yet. The direction is fully confirmed. The speed is roughly four times faster than the four-year rule of thumb still used in most desk models.
The common phrasing is "grade drops 0.1 percentage points every four years." Official statistics show the national average fell from ~1.66% in 2024 to ~1.57% in 2025 — a single-year move that covered four years of the folklore.
Consequence: any mine-life model built on the four-year rule systematically overstates remaining high-grade tonnes, and the error grows linearly with the horizon.
1.5% — RKEF economic floor. Below this, unit power and depreciation are spread across too little metal.
1.0–1.3% — HPAL absorption band. Depletion, not battery demand alone, is the geological driver behind the hydrometallurgical pivot.
| Original claim | Verifiable evidence | Verdict | Trading impact |
|---|---|---|---|
| Mainstream grade was 2.0–2.5% around 2006 | Industry oral history; no independently citable time series found in this pass. Direction is consistent with "mine the best rock first." | No indep. source | Usable as narrative, not for models |
| Traded and mined grade now 1.4–1.5% | Spot deals concentrate at 1.3–1.4%; official benchmark is quoted in 1.4% / 1.5% / 1.6% tiers, with 1.4% CIF around USD 55/wmt. | Confirmed | 1.6% is now scarcity-priced; premium is durable |
| Grade drops 0.1pp every four years | Official national average ~1.66% in 2024; saprolite average ~1.57% in 2025. Single-year move is near the four-year rule of thumb. | Materially understated | Mine-life & long-term pricing need repricing |
| 400+ mining permits; reserve declarations inflated | Active nickel mining permits in Sulawesi rose from 1 in 2005 to a 2022 peak of 408; approval cycles tightened from three-year to one-year windows. | Count confirmed | Inflation not quantifiable; diligence per site |
| Internal haul distance up from <5 km to >20 km | No independently citable industry statistic found. Consistent with the pattern of near-shore surface deposits being exhausted and mining moving inland. | No indep. source | Treat as a per-site cost assumption to test |
| Average NPI nickel content down from 13% to 11% | Public quarterly filings from a major Indonesian RKEF producer show NPI Ni content moved from ~12.1% to ~11%; NPI tonnage +4.4% but contained metal fell. | Direction OK; base too high | Model 12.1% → 11% for contained-metal math |
| Grade decline pushes migration to HPAL | HPAL feed is 1.0–1.3% limonite; the 120 kt Pomalaa MHP project reaches mechanical completion in Aug 2026, needing ~21 Mt limonite/yr. | Confirmed | Limonite shifts from waste to tight product |
Feed ≥1.5% saprolite. Grade decline directly pushes down unit metal output per furnace, so energy and depreciation dilute onto less nickel. Indonesia RKEF utilisation is down from 84% to 76% — some South & Central Sulawesi lines run below 50%. Operators hold low burn rather than cold-shut, because a cold restart takes months.
Feed 1.0–1.3% limonite. Turns former waste into revenue and physically extends mine life. But the new benchmark formula that prices in cobalt, iron and chrome content lifts limonite reference prices sharply — policy is compressing the raw-material cost advantage that HPAL used to enjoy.
From 15 Apr 2026 the HPM formula raises the grade-correction coefficient and adds associated elements. A 1.4% saprolite reference is now ~USD 53.6/wmt vs a spot ~USD 55.1 — the premium compressed to roughly USD 1.3. Policy and market prints are converging.
Indonesia's nickel industry runs on two corridors: central-east Sulawesi (Morowali–Konawe–Kolaka) and North Maluku (Weda Bay–Obi). Once quotas tightened, feedstock self-sufficiency became the single biggest differentiator between clusters.
Depletion has lifted the entire Indonesian cost curve. That lift does not reverse when quotas loosen. Quotas are reversible. Geology is not.
Near-term price direction is still dominated by policy, not fundamentals: the July HPM print cut ~6% while the market is openly divided on whether quotas will be widened.
Medium-term, pyrometallurgical capacity is under rationalisation pressure. HPAL absorbs the low-grade tail, but is itself squeezed by sulphur supply and the new benchmark formula.
One · Quota top-up. Rumours of an expansion coexist with the Ministry's line that only critically short smelters will be topped up. Two narratives, not yet reconciled.
Two · Philippine landing cadence. Weather windows and voyage counts determine the actual substitute tonnage — paper capacity is not the constraint.
Three · Sulphur & sulphuric acid. The real bottleneck for the HPAL pivot. Any shipping disruption transmits directly into MHP utilisation.