METHOD FOR DEVELOPMENT OF DEEP PLACER DEPOSITS Russian patent published in 1998 - IPC

FIELD: mining technology. SUBSTANCE: this relates to dredging of thick productive sediments in development of placer deposits at improved ecology of dredging operations. In process of preparatory work before start of dredging operations, additionally carried out is extraction of barren rock beyond perimeter of workable reserves and within limits of dumping boundaries. Sand is piled in dumps at maximal possible relation of depth and width for dredge in given placer deposit. More reach sands are placed in lower part of dump, and leaner sands are placed atop. After that, placed to surface of dump is layer of barren rock. Sands are flooded down to ground water level in valley. During dredging of sands, after regular advancement, upper edge of work face is caved down. This procedure reduces loss of mineral being extracted and cuts cost of nature reclamation expenditure. EFFECT: higher efficiency. 3 dwg