by 1879, the first year of the Colorado Silver Boom. The town of Gilman and nearby mining operations were developed in the 1880s by John Clinton, a prospector, judge, and speculator from nearby Red Cliff. In 1887, gold and silver were discovered in two vertical chimneys at the Ground Hog Mine, which continued to produce gold and silver ore until the 1920s. In the 1880s, Clinton acquired a number of mining operations in the vicinity, including the profitable Iron Mask, noted for its numerous caverns with crystal formations. Clinton developed the area as a town and improved the mining operations with higher capitalization. The town, which Clinton developed in order to keep miners at the site, was initially named for him. He donated the land for its initial schoolhouse and built its first boarding house. The Denver and Rio Grande Railroad reached the mining camp of Belden at the base of the cliff in 1882. By 1899, it had a population of approximately 300, as well as a newspaper, called the Gilman Enterprise. As they reached the deeper primary sulfide ores, the miners found that the ore contained so much zinc that the smelters refused to buy it. A roaster and magnetic separator were installed in 1905 to separate out the zinc minerals, turning the problem into an asset. The mining operations transitioned increasingly to zinc, although the Eagle Mine was still the leading producer of silver in the state in 1930. The New Jersey Zinc Company entered Gilman in 1912, and over a period of years bought all the principal mines and the entire townsite. Zinc was the economic mainstay until 1931, when low zinc prices forced the company to switch to mining copper-silver ores. Zinc production resumed in 1941, and remained the principal product of the mines until they were closed in the 1980s. The town population was a few hundred in the 1960s. At one time, the town had an infirmary, grocery store, and bowling alley. The town experienced labor strife several times in the 1950s, partly inflamed by the out-of-state corporate ownership. By 1970, total production at the mines was 10 million tons of ore; 393,000 troy ounces (12,200 kg) of gold; 66,000,000 troy ounces (2,100,000 kg) of silver; 105,000 tons of copper; 148,000 tons of lead; and 858,000 tons of zinc. After the closure of the mine and the abandonment of the town, a area,