| In order to ensure the stope safety of Dayingezhuang Gold Mine and improve resource recovery, through investigating some stope pillars on the level of －380, －496, －556, －616, it is concluded that parts of pillars controlled by structure of direction showing different failure modes which can be divided into parallel between joint and pillars, skew between joint set and pillars and parallel between joint and roof. Through establishing the relationship between width of pillar, stope span, mining depth and safety coefficient of pillars, the result shows that the effect of pillar width on safety coefficient is the most important one, followed by mining depth, and the last one is stope span. Through evaluating the stability of pillars, safety coefficient of every pillar and unstable pillars are got. Finally by means of calculating, the conclusion can be drawn that the minimal roof span is 8.2 meters and the width of the pillar should be greater than 4.1 meters. |