For most of us, it’s remarkable enough to access the Internet from a plane 10,000 meters in the air. But when Swedish process-control engineer Ulf Olsson does that – as he did recently while flying over Arizona – he’s also monitoring an iron-ore drill 1,000 meters below the earth’s surface in northern Sweden, thanks to underground Wi-Fi.

While cities like Philadelphia wait for citywide Wi-Fi networks to come on line, the world’s iron, coal, and copper mines are getting fat wireless broadband pipes. By early next year, the mine in Kiruna, Sweden – 150 kilometers north of the Arctic Circle – will complete its installation of Wi-Fi-linked drills. A German mining company, Deutsche Steinkohle, is installing several hundred Wi-Fi hot spots in its coal mines. So is a copper mine in Chile called El Teniente, which claims to be the world’s largest.

Miners aren’t blogging from the tunnels – yet. In Kiruna, information from drills and trucks – such as their positions and the weight of their loads – is relayed via wireless base stations to a computer in a control room above ground. (Weight is an important datum; it tells the operator how good the ore is. The heavier the better.) With Wi-Fi networks, fewer miners have to face the risks of working underground – and those who do have a more durable link to the outside.

LKAB, the company that operates the Kiruna mine, has experimented with wireless networks before, but Wi-Fi offers cheap standardized components and is the newest tool for boosting mine safety and productivity, says Christoph Mueller, president of Embigence, an automation company in Ladbergen, Germany. “Mine companies can’t build bigger machines. Now productivity growth has to come from optimization,” he says. With Wi-Fi, he says, mining companies gain cheap real-time information – and workers stay safe.