South African companies (among others) racing to build new “ultra deep” mines–deepest now at 2.5 miles, where rocks shatter like glass, temperatures are nearly unmanageable and escalating risks to miners are huge. But gold prices are at historic highs…and there’s big, record-breaking money to be made. The mine that is going to be 2.5 miles deep will have temperatures around 55 degrees Celsius. The mine operators are going to have to find new ways to keep their mines cool. As well no cable can be 2.5 miles long so they will also have to find new ways to get people down to these depths. It is truly remarkable how far we are going to extract natural resources from the Earth.