METHOD OF NOBLE METALS RECOVERY FROM ONES AT THEIR PLACES OF OCCURRENCE BY UNDERGROUND LEACHING Russian patent published in 2002 - IPC

FIELD: geotechnological methods of noble metals recovery; applicable in underground leaching of metals from ores at their places of occurrences. SUBSTANCE: method includes drilling of injection, pumping-out and observation holes in ore-bearing horizon supply of solution of leaching reagents in presence of oxidizers into treated blocks of ore body through system of injection holes and pumping-out of productive solution through system of pumping-out holes with subsequent processing of productive solution by methods of sorption and/or cementation, and control of leaching process through observation holes. In the course of exploration, geotechnical properties of ore of partially flooded ore body are determined, and ore body is subdivided into ore blocks including nonflooded and flooded zones. Impervious curtain on external contour of ore body is constructed through its entire worked thickness, and on boundaries between ore bodies, said curtains are installed only for thickness of nonflooded part of ore body, and noble metals are leached. A part of leaching solution is supplied to nonflooded zone through system of newly established irrigation devices in the form of irrigation trenches, draining hole or irrigation ponds in infiltration conditions. The other part of leaching solution is supplied to flooded zone through system of injection holes in filtering conditions in ratio determined as function of ore geotechnical properties of treated ore block and its geometric sizes are ensuring simultaneous treatment of its nonflooded and flooded zones. Spacing density of holes and/or irrigation devices are determined as function of distances between them. For intensification of leaching process of nonflooded zone of ore body, after irreversible decrease of concentration of recovered metal in productive solution, alternately supplied to irrigation devices is gaseous oxidizer and mother liquors of sorption with pH of productive solution is maintained below 6.0. EFFECT: higher efficiency of underground leaching of part of flooded ore body. 8 cl, 2 tbl, 1 ex