The Mining Trap
More Australian retail investors have permanently destroyed capital in mining stocks than in almost any other sector. They buy BHP when iron ore is at $160/t and earnings look extraordinary — then hold through the commodity cycle crash.
The mistake is not owning mining stocks. It is valuing them at the wrong point in the cycle.
The Fundamental Rule: Normalised Earnings
Never value a miner on current earnings. Use the 5-7 year average across a full commodity cycle as your baseline.
The critical insight: at $160/t iron ore, BHP's Graham Number looks attractive ($57) against a $43 price. At $80/t, that same price is 74% above the Graham Number ($25).
The price has not changed. The valuation has completely reversed. This is the mining cycle trap.
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Start Free Trial — Pro Standard from $7/moThe Normalisation Process
Step 1: Collect EPS for the last 5-7 years (include a full commodity cycle — boom AND bust) Step 2: Average them, excluding extraordinary items (asset writedowns, one-off gains) Step 3: Use this normalised EPS in your Graham Number and DCF
| Miner | 5-Yr Norm. EPS | Norm. Graham No. | Current Price | Verdict |
|---|---|---|---|---|
| BHP | ~$3.50 AUD | ~$37 | ~$43 | Slight premium |
| RIO | ~$9.20 AUD | ~$48 | ~$120 | Well above norm |
| FMG | ~$2.80 AUD | ~$22 | ~$20 | Near fair value |
| WDS | ~$1.65 AUD | ~$28 | ~$25 | Near fair value |
Approximate figures — run current analysis at Value Calc for updated numbers
The Quality Spectrum
Tier 1 — Value investor grade: BHP, Rio Tinto (RIO), Fortescue (FMG), Woodside (WDS) - Global scale, lowest-cost operations, investment-grade balance sheets - Can survive commodity downturns without equity raises - Pay dividends even at trough prices
Tier 2 — Speculative (not for value investing): Mid-tier single-commodity miners - Need commodity prices to stay high to be profitable - Require 40-50% margin of safety minimum - Higher risk of equity dilution at the bottom
Tier 3 — Avoid: Pre-revenue explorers, single-drill-hole stories - Nothing to value with Graham or DCF frameworks - Pure speculation
The Four Balance Sheet Tests
Before buying any miner, check these four metrics:
- Net debt / EBITDA: Should be below 1.5× at mid-cycle earnings. Above 2.5× is dangerous in a downturn.
- All-in sustaining cost (AISC): For gold miners and iron ore producers — how does cost compare to spot price? Low-cost producers survive downturns.
- Reserve life: Ore reserve years at current production rate. Under 10 years means you are paying for a depleting asset.
- Capital allocation discipline: Do they buy back shares at the bottom, not at the top? Do they grow via organic development, not overpriced acquisitions?
The Reward for Getting It Right
Investors who bought BHP below $16 in 2015-16 (iron ore crashed to $40/t, headlines were catastrophic) saw their position triple by 2021. Total return including dividends was over 5×.
Those who bought BHP at the 2011 peak ($48+) waited 10 years just to break even.
The same business. Completely different outcomes. The only difference was the price paid relative to normalised intrinsic value.
When to Act
Mining stocks offer entry points 2-3 times per decade. Signs the opportunity is arriving: - Commodity prices down 30-50% from peak - Mining company headlines: "profit warning," "dividend cut," "balance sheet review" - Major brokers downgrading to "sell" after massive price falls (the most reliable buy signal) - P/B ratio near or below 1.0
Use Value Calc to have your normalised intrinsic value calculations ready. When the price arrives, you need to act — it rarely stays cheap for long.