One of very few remnants of water-powered ore-grinding machines. Numerous in the west from 1840s through 1880s. Chunks of gold bearing ore were ground to powder on this stone base by heavy “drag-stones” geared to a water wheel. Gold was recovered by amalgamation with mercury. The Blewett arrastra was built in 1861 when some 260 miners worked here, and was active until 1880. An arrastra near Liberty, about 10 miles south, was used until 1932.
The arrastra was about twelve feet in diameter and was three feet deep, built from granite brought from a nearby outcrop. The arrastra was powered by a overshot water wheel twenty six feet in diameter. Granite boulders would be attached to a chain, known as drag blocks would crush the ore to a fine powder.
Originally there were two arrastras near this site, and several older ones up Culver Gulch.
Source: Bulletin 6 Geology and Ore Deposits of Blewett Mining District Charles E. Weaver 1911