Gentry Gulch Arrastra
The Spanish first introduced the arrastra to the New World in the 1500's. The word arrastra comes from the Spanish word "arrastre," meaning to drag along the ground. When ore was quarried out of the hard rock mines, the quartz had to be crushed to free the gold. The arrastra was the earliest and simplest device introduced into the remote areas of the California Gold Fields to do this operation.
The simplest form of the arrastra was a flat-bottomed drag stone placed in a circular, rock-lined pit and connected to a center post by a long arm. With a horse, mule or person providing power at the other end of the arm, the stone was dragged slowly around in a circle.
Ore placed between the stone floor and drag stone was crushed into a coarse powder after which water and quicksilver were added. The resulting slurry was then moved to sluices (troughs) where the gold was recovered.
The floor stones of this arrastra were stolen from the National Forest land, Gentry Gulch area, in 1997. In 1998 the National Forest Service seized the arrastra pieces during a search of private property.
Thanks to the efforts of the Stanislaus National Forest Groveland Ranger District, the title to the drag stone and all of the floor stones of this arrastra was transferred to the Groveland Yosemite Gateway Museum in 2003. It was reconstructed by local volunteers in March of 2004.
Click here to see an etching of an arrastra at work.