Randgold Resources had to haul heavy equipment more than 1 000 miles to build the roads and hydropower plants needed to construct its Kibali gold mine, the biggest in Democratic Republic of Congo. The sprawling facility in a remote corner of a country the size of Western Europe is a high-tech operation. In one tunnel deep underground, a $1.3-million, 68-metric-ton remote-controlled digger heaves ore out of a cavernous blast hole. The ventilation system hums as 50-ton loads are slowly humped along the 3-kilometer (2-mile) track back to the surface.
