This invention relates generally to the field of placer mining, and more particularly to an improved form of continuous run sluice box adapted for operation with little if any down time for cleaning.
In the traditional placer mining process, large amounts of ore and sands are continuously washed in a sluice which is not subjected to constant vibration. The heavier precious metal and accompanying black sands sink to the bottom of the sluice, and the lighter weight sands and other other impurities are washed away. Large scale placer mining is relatively inefficient, in that the black sands which accompany the precious metals often, with further refining, will realize other products which are worth as much or more as the recovered precious metal. In the traditional sluice, the riffles or transversely extending walls disposed at substantially equally spaced intervals, periodically become filled and packed with recovered material, and operation must then be halted so that the material can be removed, usually as a hand operation. During this period, no washing of ore can take place.
In the above identified copending application, a construction is disclosed in which the device is provided with a pair of oppositely facing sluice channels, mounted on a common frame for rotation about a single longitudinal axis. The upper sluice channel, at any one moment, is in operation, while the other sluice channel is downwardly faced to facilitate the freeing of collected material from the riffles by an air or water flushing operation, so that it may drop under the action of gravity into a holding tank or other receptacle for collection. This flushing is accompanied by the normal vibration which occurs during operation of the sluice imparted by a reciprocating motor driven means, and, in addition, an ultrasonic vibration is also introduced to facilitate the loosening of collected material. While this construction is quite effective, I have found that the clearing of the riffles can be substantially improved while simultaneously improving the mineral collecting ability of the riffle structure.