Urban Mining

On another episode, we talk about how mines have a large environmental footprint. Think of a giant pit, with huge machines digging out ore. By contrast, think of your old smart phone. In one ton of discarded phones there’s 80 times more gold than in one ton of ore.  Electronic waste, like phones and computers, contains gold, silver, palladium and rare earth elements. Old batteries contain lithium, cadmium and other heavy metals.  Construction and demolition debris contains copper from piping and air conditioning, and steel from rebar and beams.  Old cars and trucks contain steel, aluminum and other metals.  This can make cities a repository of metals more concentrated than any mine. And makes this waste the resource for a new industry called ‘urban mining.’ The challenge is gathering that varied waste from across the urban environment, then sorting and disassembling it to be processed. That takes energy, time, labor and money. But new recycling programs, often powered by AI, sort materials with magnets and robots, then use mechanical shredders and chemical solvents to break them down into simpler components. Producing metals this way uses less energy and water than mining and processing new ore, with potentially less environmental impact – while also reducing the need for new metals, sometimes imported from unfriendly countries.  In the future, more metal will come from these sources much closer to home.