METHOD FOR MINING DIFFICULT-TO-DREDGE PLACERS Russian patent published in 1995 - IPC

FIELD: mining industry. SUBSTANCE: trench during placer opening is extended through the entire width of placer. Excavator is installed on block of untouched barren rocks and dredging is accomplished from one station. Waste rocks are arranged on flanks of trench and on part of base rock adjacent to trench flanks by forming drainage channel at lower edge of trench slope. This is effected by increasing dump in direction of flank with segregation of rocks in filling and laying boulders along channel. Then barren rocks are placed on base rock and dump slopes. After formation of new trench, excavator is moved to next station, and operations are repeated in the same order. EFFECT: reduced costs in mining placers of small width with considerable thickness of overburden rocks due to reduced volume of drainage and subsequent flooding of sands. 3 cl, 2 dwg