Anglo’s De Beers writedown and Teck merger: project and supply notes for engineers
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Anglo American is preparing a third impairment of De Beers in as many years, after average realised prices fell 7% to $142/ct in 2025 and an adjusted rough price index drop of 25% signalled persistent diamond market weakness, even as Q4 sales rose to 5.9 million carats and $571m revenue. The potential writedown complicates Anglo’s planned sale of its 85% De Beers stake amid competing interest from a Gareth Penny-led consortium, Botswana and Namibia, alongside stalled divestment of Australian steelmaking coal assets. In parallel, Anglo-Teck has cut 2026 copper guidance to 700,000–760,000 tonnes and plans a 15 km conveyor to integrate Collahuasi ore with Teck’s Quebrada Blanca processing facilities, tightening near-term supply expectations for copper.
Technical Brief
- Anglo previously booked De Beers impairments of $1.6 billion (2024) and $2.9 billion (2025).
- Botswana supplies about 70% of De Beers’ annual rough diamond output, underpinning mine-plan decisions.
- Ownership structure remains 85% Anglo, 15% Botswana, complicating any change-of-control transaction or governance reset.
- Q4 2025 sales mix included inventory sold below cost, largely lower-value goods, distorting realised price signals.
- Prospective De Beers buyers include a Gareth Penny–led consortium, with Bruce Cleaver also cited as interested.
- Namibia has publicly expressed interest in acquiring a stake or control, adding another state-party to negotiations.
- Anglo’s restructuring already saw demerger of its platinum arm Amplats (now Valterra) in June 2025.
Our Take
With Anglo American targeting a $53 billion merger with Teck Resources heavily weighted to steelmaking coal and copper, the repeated De Beers impairments effectively tilt the portfolio narrative further away from diamonds toward bulk and base metals in Latin America and Canada.
Botswana’s 15% stake in De Beers and its roughly 70% contribution to rough diamond supply give the government significant leverage over any restructuring or potential separation of the diamond business as Anglo refocuses around assets like Collahuasi, Quebrada Blanca and Quellaveco.
Across our 917 Mining stories, copper repeatedly appears as the ‘growth’ commodity—here the 5% miss versus Goldman Sachs’ copper output estimate and Quellaveco’s 10% shortfall highlight execution risk just as Anglo is pitching scale and reliability in copper to justify the Teck combination.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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