Stability evaluation of room-and-pillar rock salt mines by using a flat jack technique - A case study

Room-and-pillar mining is commonly employed for the extraction of rock salt in underground mines. Pillar stress a major concern these mines as it directly related to stability and mineral recovery. In this study flat jack method was used measure pillar stresses three Pakistan. The field work included determination in-situ stress, elastic modulus, recording variables (pillar length width, height width opening, opening ratio, overburden height) collection block samples. geomechanical properties (uniaxial compressive strength, Young's Brazilian tensile density) were also determined estimate factor safety (both estimated actual). It found that measured are proportional values, with their magnitude ranging from 6.05 MPa 11.97 Mpa, pillars be stable. Regression analysis performed develop statistical models modulus. Finally quick guideline chart developed determine suitable given span required level safety. Keywords: jack, room-and-pillar mining, safety, regression analysis.