METHOD OF REPEATED DREDGING OF TECHNOGENIC PLACER Russian patent published in 2003 - IPC

FIELD: mining industry; applicable in development of reserves of technogenic placers dredged before. SUBSTANCE: method includes removal of upper layers of placer into dump and combined dredging of remaining technogenic layers with layers of ledge zone. Technogenic placer is divided into standard and substandard layers according to vertical limit of useful component content in rock mass, with removal of substandard layers to external dumps. Standard pebble-sand-clay refuse layers are extracted and reexcavated, first, into intermediate and then, into constant fill located in standard layer in ledge zone for subsequent combined dredging. EFFECT: increased content of useful component in dredged rock mass. 4 cl, 4 dwg, 1 tbl