In 1864, two miners staked a claim for gold on a lonely bluff near the Continental Divide at the headwaters of the Clark Fork River. The gold soon played out, but miners discovered something else: silver.

As a source of wealth, silver was as good as gold, but the mining techniques were quite different. Gold can be panned from streams by individuals working alone and can be sold as powder or lumps. Silver, however, requires underground mining to extract the ore, which then must be refined by smelters. As mining at Butte developed in the 1870s, the era of the independent prospector passed and corporate mining began. Then, as silver ran out, copper became the lodestone of Butte mining.

The transcontinental railroads vied for lucrative contracts to take the refined metal to world markets. The railroads also brought in immigrants to work the deep veins. Railroads were built between Butte and Anaconda and between Butte and Great Falls to take the ore to smelters.

Butte, soon to be known as “the richest hill on earth,” was dominated by smokestacks, peopled by immigrants, and undercut with 10,000 miles of mineshafts. It quickly became Montana’s largest and wealthiest city. The city never slept: Miners worked the veins 24 hours a day, and bars, restaurants, and other businesses were always open to serve their customers. The huge influx of immigrants that poured into Butte during this period from Central Europe, Italy, Cornwall, Ireland, and China gave Butte its cosmopolitan flavor and its ethnic neighborhoods.

Other factors were not so positive. Butte was an environmental disaster. The pollution from the smelters soon killed all the vegetation within a 20-mile radius. The trees that weren’t killed by smoke were cut for mine supports or to fuel the smelters. Smelting also used vast amounts of water, which was simply returned to streams laden with toxic chemicals and minerals. The mining process produced mountains of tailings, some of which were radioactive. Entire communities were built on these tailings.