METHOD OF ROCK MASS PROTECTION FROM ROCK PRESSURE Russian patent published in 2002 - IPC

FIELD: mining industry; applicable in underground mining of mineral deposits under conditions of high rock pressure. SUBSTANCE: method includes formation of vertical relieving stepped slot to the strike and dip of ore body, beyond worked block, for distance determined by line of intersection of planes located at an angle of internal friction of rocks. One of said planes is tangent to boundaries of worked block, while the other, is located in slot plane which runs beyond boundaries of ore block worked by workings along the strike and dip of ore body. Slot is filled with broken ore in lumps equalling 0.3-0.5 slot width, and block bottom is formed. Stresses acting in rock mass are measured and rock pressure is controlled by partial drawing of broken ore from slot, if stresses attain critical values. Relieving slot is formed with expanding sides at an angle of 2-5 deg. Side conjugated borehole pairs are drilled parallel to vertical side of relieving slot with width of 0.2-0.25 m and opposite single boreholes are drilled at an angle of 2-5 deg parallel to the other side of relieving slot. Intersected mine workings are connected by artificial branch pipes through caved space of slot. Ends of branch pipes are installed into mine workings of block mass to depth of 1-2 m, and stressed state of rock mass in block is controlled by value of displacement of branch pipe ends relative to contour of mine working. EFFECT: increased efficiency of protection and higher safety of mining operations. 4 dwg