For four decades, the American coalfields hosted an engineering arms race measured in cubic metres of bucket. It ended not with a bigger machine, but with a deliberate retreat. The single largest mobile land machine ever built, the Marion 6360 "Captain," was commissioned in 1965 and destroyed by fire in 1991. No shovel has approached its scale since, and the machines that replaced it were smaller by design.

Indium is one of the metals you never see but use constantly. As indium tin oxide, it forms the transparent conductive coating on nearly every LCD and touchscreen, and that single application still accounts for most global consumption, according to the USGS. But the metal's role is broadening. Its compounds now sit inside the high-speed optical chips that route data through AI data centers, a shift that has turned a quiet, display-driven material into one buyers watch closely, especially as China refines about 70% of it and has begun tightening the flow.

In September 2022, the Pentagon quietly stopped taking delivery of new F-35 fighter jets. The reason was not a design flaw or a manufacturing defect. A single small magnet inside the plane's engine had been made using an alloy from China, which is banned under U.S. defense procurement law.

One consumer-electronics company is now worth more than every publicly traded mining company on Earth combined. The graphic above captures the June 5 snapshot, when the 317 publicly traded miners tracked by CompaniesMarketCap were worth about $3.48 trillion