Many miners think drywashers are only for use in the desert.
The truth is they are useful any place where the material is very dry. Since drywashers are not quite as efficient as devices that use water for separation, wet methods should be used if possible. The recovery rate of a drywasher decreases dramatically as the moisture content of the material increases so make sure the material you are working is very dry. The newer type uses a gas powered blower and a device to cause a high frequency vibration of the riffle tray. Some of the larger drywashers of this type incorporate an exhaust heater in the blower to help dry the material.