Monitoring And Analysis On Stability Of Mine Prop In Coastal Mining Of Sanshandao Gold Mine

There are abundant mineral resources under the sea.It is a worldwide problem to realize safe and efficient mining of underwater deposits.There are few experiences for reference.Therefore,it is of great theoretical value and practical significance to carry out the research on the stability monitoring and control technology of the mine prop in coastal mining.Based on the engineering background of the mining of the Northeast limb ore body under the seashore of Sanshandao Gold Mine,this paper theoretically studies the safety and feasibility of the isolation pillar size determined by the engineering experience.Combined with the methods of field investigation,experience analysis,theoretical calculation and numerical simulation,it studies the stability of the isolation pillar above-115m in the Northeast limb ore section under the seashore of Sanshandao gold mine,The reasonable size of isolated pillar is theoretically analyzed and demonstrated,and suitable mining method is provided for the mining of underlying ore body,so as to improve the mine output and promote the development of mining industry.Around this research topic,this paper mainly carried out the following research work.(1)By searching the literature and summing up the mining experience under water at home and abroad,it is found that the isolation pillar and filling mining method are the effective methods and means to control the surface movement and rock deformation of"three lower" mining,including coastal mining.Through in-depth study of the literature,this paper lays a theoretical foundation for the later research.(2)By investigating and summarizing the relevant geological data,the engineering geology,hydrogeology and mining status of the northeast wing of the mining area are summarized and analyzed,and the physical and mechanical parameters of the rock in the mining area are determined to provide calculation parameters for the later theoretical calculation and numerical simulation.(3)The field investigation and monitoring on the stability of isolated pillars in Northeast mining area were carried out.According to the field investigation,there is no obvious caving zone in the overlying strata,only fracture zone and deformation zone;The height of water flowing fractured zone is generally 30～40m;Using the level to observe the rock movement,the law of rock movement and deformation in the mining area is analyzed.The settlement law of the shallow and middle strata tends to be gentle.Considering the field monitoring,the isolated pillar in the northeast wing mining area is stable.(4)Based on the empirical formula,theoretical calculation and numerical simulation,the safety thickness of the subsea separation pillar in the northeast wing ore section is more than 40m.Considering the results of field investigation and monitoring,under the premise of strengthening technical measures and means,it is safe to set the isolation pillar at-115m level.(5)This paper puts forward three mining methods for mining under the isolated pillar,and recommends the upward slicing(drift)cemented filling mining method with reserved ore pillar to form a frame roof protection structure,and ensure the safety of mining through roof connection and filling.