The Mayflower Mill, a national historic landmark located two miles northeast of Silverton in Arrastra Gulch, is open for self-guided tours in the summer months. A gift shop is run by the San Juan Historical Society, which owns the mill.
The mill was built in 1929 with the latest in technology to recover gold, silver, lead, zinc, and copper from ore that was taken out of the Mayflower mine and delivered to the mill by an 9,526-foot-long aerial tramway. The improved process, introduced in 1912, used gravity and flotation to efficiently separate valuable minerals in low-grade ores at a time when high-grade ores were rapidly becoming depleted.
In receiving the historic designation, the mill was cited as the only intact and functional late 1920s-era, wooden gravitational selective flotation mill in Colorado and one of only four such mills still in existence in the country. The complex includes the mill building, conveyor and crushing plant, tram terminal, water and coal storage tanks, and mill office/assay building.
The Mayflower Mill was the dream of Charles A. Chase, a successful mine manager at the Liberty Bell near Telluride. The mill was built at a cost of $375,000 by Stearns-Roger Manufacturing Co. of Denver, using pre-framed Oregon fir, innovative steam shovel and dump trucks coming onto the market, and the latest technology. It began operations in 1930 and continued until 1991, except for a 12-year hiatus.
The mill handled 9.7 million tons of ore, producing 1.9 million ounces of gold; 30 million ounces of silver, and 1 million tons of other metals, according to the historical society.
The mill was officially known as the Shenandoah-Dives Mill, but Silverton residents referred to it as the Mayflower Mill because it served the Mayflower mine. The multi-level mill building is 252 feet long and has sections 90 feet and 106 feet wide. It has a wood frame and corrugated metal on the walls and roof.
The mill is reached by heading north out of Silverton on County Road 2 (formerly County Road 100) for two miles. The mill is on the north side of the road.