Rio Tinto’s Diavik diamond mine concludes operations in Canada

Diavik completed its final day of production after 23 years, having produced over 150 million carats; closure activities run through 2029 and remaining rough diamonds will be polished and sold through 2026 and beyond. Rio Tinto reported underlying H2 2025 EBITDA of $25.4bn and net profit of $10.9bn, missing Goldman Sachs’ estimates of $25.9bn and $11.2bn and prompting a downgrade to Neutral. The company secured $1.175bn financing for the Rincon lithium project (targeting 60,000 tpa battery‑grade lithium carbonate), agreed a A$1.1bn JV to finish an 8 GL/year desalination plant, and signed a MoU with CATL on electrification and recycling; market cap is $147.6bn with a 5.81% dividend yield.

Analysis

The depletion of a long-lived, high-quality natural diamond source tightens the upstream supply curve in a concentrated market, increasing price volatility for large-gem rough and compressing visibility for midstream cutters who target size-consistent parcels. Expect midstream inventory days to fall and bidding dispersion at sight sales to widen; that increases working capital draw for sightholders and raises the marginal value of near-term access to polished inventory by as much as one quarter of typical turnover (6–12 weeks) in stressed months.

For a diversified miner with active capital allocation into battery metals and water infrastructure, the cross-commodity optionality matters: derisking a financed lithium brine project materially shortens the time to monetization of high-margin battery carbonate volumes, but execution and sovereign/brine yield risk in South America remain dominant 12–36 month tail risks. Conversely, investing in desalination and closure remediation shifts cash flow timing — near-term free cash flow will be absorbed by capex and closure provisioning while de-risking longer-run iron-ore throughput and ESG liabilities.

Analyst downgrades and a muted earnings beat create a near-term sentiment headwind that can be overstated by 5–10% in equity price swings relative to intrinsic value when macro commodity prices are stable; these moves often reverse within 3–6 months if project milestones (financing drawdowns, permitting, offtake letters) are met. The main reversers are: a meaningful CRU/benchmark lithium price move >15% or a visible acceleration in project execution evidenced by draws against committed financing within 6 months.

Key Decisions for Investors

• Long RIO equity (12-month horizon): Initiate on a pullback of ~5–10% from current levels to capture derisking optionality in lithium + desalination cashflows. Position size 3–5% portfolio; target total return +25–40% vs a 12% downside stop (event-driven, not volatility).
• Call-spread + put-sell structured trade (9–12 months): Buy a 12-month call spread ~25%/60% OTM (1x) financed by selling a 90-day 10% OTM put (1x) on RIO to express asymmetric upside while funding downside protection. Expected payoff: limited max loss ≈ premium received; potential 3:1+ upside if commodity/project catalysts materialize.
• Relative-value pair (6–18 months): Long RIO / Short BHP (equal notional exposure) to isolate lithium/desalination optionality versus pure iron-ore cyclicality. Target spread widening 20–30%; cut if both names rally >15% on broad iron-ore surge (signal of common-factor move).
• Tactical hedge (0–3 months): Buy GS 3-month put spread as cheap macro/banking tail protection if risk-off spikes from commodity-driven margin shocks; alternatively use market-wide VIX or commodity-volatility instruments if liquidity is better. Keep hedge size at 1–2% portfolio notional.