The Leadville mining district, located in the Colorado Mineral Belt, was the most productive silver-mining district in the state of Colorado and hosts one of the largest lead-zinc-silver deposits in the world. Oro City, an early Colorado gold placer mining town located about a mile east of Leadville in California Gulch, was the location to one of the richest placer gold strikes in Colorado, with estimated gold production of 120,000–150,000 ozt (8,200–10,300 lb; 3,700–4,700 kg), worth $2.5 to $3 million at the then-price of $20.67 per troy ounce.