Trail 2026-10-11 (c, third session)

Budget: 15 fetched pages or 40 tool calls. Orientation: steer, index, research-values, dead-ends, trail-2026-10-11, trail-2026-10-11-b, macro-view.

Thread chosen: macro-view (within thread-transition), steer item 1: test the thinnest of the three crises. The thinnest is resources: it rests on one source family (IEA) and has been read only as concentration, never as depletion or physical cost (ore grades, energy cost of extraction). The dollar-haven question is a recorded dead end, so I'm not retrying it.

Hops

Tooling: web_extract is still broken. I read through search text from the free-tier fallback, and through the browser where it worked. MDPI returned Access Denied, and Cochilco's own page timed out.

1. Expect: a primary paper on copper ore-grade decline and energy, which tests the leg as physical cost. -> Calvo, Mudd et al. 2016 (https://www.mdpi.com/2079-9276/5/4/36, search text): grade down ~25% over 2003-13 across 25 mines, energy +46% against output +30%. For.
2. Expect: West 2011, the classic "is grade decline really depletion?" counter. -> got only citation lists (RePEc). Taught nothing new.
3. Expect: Cochilco's measured national series, a primary and current figure. -> search pointed to a summary of the 2024 report. Read it in the browser (https://ax.legal/2025/12/03/energy-trends-in-chilean-mining-what-the-2024-cochilco-report-shows/): energy +53.9% since 2010 for +1.6% copper; 36.2 GJ/t (+51.5%); diesel is 92% of fuels. Surprise.
4. Expect: the strongest published counter (Rötzer & Schmidt 2018). -> MDPI blocked the browser; search text gave the conclusion: falling grade = demand + technology, and real prices flat over the long run. What needs protecting is the environment, not the metal. Against depletion; agrees on rising cost.
5. Expect: USGS reserves over time, the neutral arbiter. -> mcs2026 appendixes: reserves 280 Mt (1970) -> 980 Mt (2024), after 712 Mt mined. Strongly against "running out".
6. Expect: Cochilco's primary page in Spanish, to confirm the 36.2 GJ/t. -> the search found the report's page and Cochilco's 2025 cost observatory (cash cost fell 5.7¢/lb on by-product credits). The browser timed out on the report page. Unconfirmed.
7. Expect: Northey/Mudd/Werner as the mediating frame. -> abstract read (stephennorthey.net): reserves, cut-off grades and ore grades move together with technology; "unresolved complexity". Confirms the map; teaches little.
8. Expect: whether AI data centres show up in copper demand (a test of last session's hunch). -> BNEF via mining.com (https://mining.com/ai-data-centers-to-worsen-copper-shortage-bnef): ~400kt/yr average, peaking at 572kt in 2028; shortfall of 6 Mt by 2035. Secondary report; kept in the trail, not added to the wiki.

Stopping rule: hops 2 and 7 taught little, but not three in a row. Stopped to write up with budget left.

Hunches (unsourced, not in wiki)

• The resources and fossil legs may be one crisis seen from two ends: metals get dearer in energy as grades fall, and the energy transition needs more metal. The renewables good news on the fossil leg (Ember) is bought partly with diesel in Chilean pits.
• The AI capex hunch gets a second foothold: data centres take ~2% of world copper demand at peak (572kt against ~27 Mt). That is small, but it is concentrated in time. My arithmetic, on BNEF figures.

End of session

Surprises

• Chile's copper mines used 54% more energy in 2024 than in 2010 to produce 1.6% more copper. Diesel, for hauling out of deeper pits, is the fastest-rising input. https://ax.legal/2025/12/03/energy-trends-in-chilean-mining-what-the-2024-cochilco-report-shows/
• At the same time, world copper reserves are 3.5x what they were in 1970, after more than twice the 1970 reserves have been mined. "Running out" fails on the data; "costing more energy and land per tonne" holds. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-appendixes.pdf

Dead end: none new. MDPI and Cochilco blocked the browser or timed out; the search text covered what was needed. Worth continuing: macro-view, resources leg. Next hop: Cochilco's own 2024 PDF, to confirm 36.2 GJ/t and get the ore-grade series it cites. Permission to chase: Valero & Valero's "thermodynamic rarity" / Thanatia (the energy cost of restoring metals from a crustal-average Earth). It is old-ish and forgotten, and would give the resources leg a single physical unit. It crosses into philosophy-of-technology (Georgescu-Roegen), so it would run as its own line. Budget used: 12 fetches/searches (of 15); ~27 tool calls (of 40).