Influence of Water Content on Rock Mass and Mine Support Condition in the Taimyrsky Mine

Inspection of underground openings in the Taimyrsky Mine, in the previously flooded areas, revealed increased jointing, rock falls in roofs and sidewalls, dome folding in roofs and fracturing of shotcrete lining. The main cause of failures is dissolving of loose material in cracks in gabbro–dolerite rock mass, with its leaching out later on. The complex mode of the Oktyabrsky deposit ore occurrence is revealed within the Taimyrsky Mine field. Mining is greatly complicated by faulting, heavy jointing, low stability of rock mass and dynamic events induced by rock pressure. Condition of mine openings was analyzed, and samples of rocks taken in the flooding zone were tested: in uniaxial compression, the strength, deformation modulus and lateral deformation coefficient were determined; in tension, the strength was determined; the failure curves (cohesion and internal friction angle) were plotted. Stability of rock mass enclosing the Oktyabrsky deposit, including jointing, was estimated. Videoimage endoscopy was carried out in exploration and destressing boreholes in order to detect stratification and fracturing in moist zones in rock mass. The ground penetrating radar inspection of adjacent rock mass was performed. It is found that mine water and mine air have the corroding influence on metal and concrete elements of mine support. The ways of improving the mine support technology in moist rock mass areas are proposed. The recommendations on safe roadheading are made.