Chilean mill

The machine was composed of two rotating wheels that would revolve over a pan filled with gold-bearing rocks.

One of the earliest such machines was built in Ballarat in Victoria, Australia during the Victorian gold rush and was combined with a sluice for extracting the gold.

[1] Another such machine in Australia was used, at the Fitzroy Iron Works, to grind clay for making firebricks.

[2] The Chilean mill, known in Chile as a "trapiche," is still in use in artisanal gold mining in the Andes Mountains.

The mill sometimes has two wheels driven by a belt attached to a motor, or a single wheel driven by mules, oxen, or other pack animals.