also be useful in rating the effectiveness of the process by comparing the radioactive level obtained subsequently in the process for this purpose a detector is shown above the conveyor although such detection equipment may be placed at any location upstream of the jig referring to fig1 feed hopper 11 optionally with a grizzly presorts and screens contaminated feed soil to remove large advantageously 5 inches and larger preferably 4 inches and larger rocks debris and the like feed hopper 11 can have a stationary screen or advantageously a vibratory type screen the hydraulically actuated cylinder for lifting the screen to dump accumulated oversize rocks debris etc may also be used optional crusher 12 may be used to reduce the size of the separated oversize fraction to permit processing of such material and thereby prevent or minimize possible damage to downstream processing equipment the crusher could be used batchwise or continuously and would advantageously be of the roller type gyratory type hammermill type and the like the material fed into hopper 11 could be processed through crusher 12 and or the oversize material from hopper 11 could be recirculated through crusher 12 thereby essentially processing all of the material available the material from hopper 11 is deposited on conveyor 13 which transports the solids to soil washer scrubber 16 conveyor 13 optionally transports the material near tramp iron magnet 14 to remove pieces of scrap iron and other magnetic metals and near metal detector 15 to remove non magnetic metals the purpose of soil washer scrubber 16 is to remove any clay coating contaminates from the coarse material remove any encrusted contaminated layers or particles other than clay from the coarse material break up any mudballs and any.