Influence of different underground mining conditions on the ground surface subsidence in the Jining coal district

Six representative working faces were selected to study the influence of different mining conditions on the ground surface subsidence at the Jining coal district.The study was achieved by means of evaluating the subsidence stage chart,performing correlation analysis and evaluating the process of subsidence and the degree of influence of phase characteristics of each working face using function fitting model.The following results were obtained.The ground subsidence of single working face,adjacent goaf working face and multi-working faces mainly comes from the active period,and the difference of subsidence between initial period and declining period is distinct.The surface movement duration of different types of working faces is different,and the main contribution comes from the different subsidence stages.The working face inclination length is the key factor affecting the stage characteristics of the subsidence process.The influence of different mining and geological conditions is in the sequence of the working face's length> the coal seam depth > the coal seam thickness > the working face advancing speed.It is easier to achieve full mining in single face and multi-faces than in the adjacent goaf face.