(Bloomberg) — Randgold Resources Ltd. 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…