Gilman, Colorado. Several mining operations had sprouted along Battle Mountain by 1879, the first year of the Colorado Silver Boom. Founded in 1886 during the Colorado Silver Boom, the town later became a center of lead and zinc mining in Colorado, centered around the now-flooded Eagle Mine. The town of Gilman and nearby mining operations were developed in the 1880s by John Clinton, a prospector, judge, and speculator from nearby Redcliff. In 1887, gold and silver were discovered in two vertical chimneys at the Ground Hog Mine, which continued to produced gold and silver ore until the 1920s.