Wire rope net structures as safety devices in mine shaft deepening

Mineral deposits have to be mined for at increasingly greater depths. The cheapest method of accessing them is the deepening of existing shafts. For both mining and deepening purposes, shafts below excavation level should be secured. A widely used method is the construction of artificial shaft bottoms. Such structures are installed at a depth of 600 to 1,000 m. In the active portion of the shaft, the carriage of personnel and handling of materials takes place. In the wonting portion, the shaft is deepened. The role of an artificial shaft bottom is to protect the personnel working on the deepening should a structural element or a machinery part fall into the shaft. The structure of an artificial shaft bollom should be able to carry the load resulting from a falling object in excess of 20 t (Mg) from a height of 1,000 m. The heavy and large artificial shaft bottom structures that are in use do not meet functional and economic requirements. There have been proposals to construct artificial shaft bottoms in the form of multiple-layer membranes composed of a networ1!. of ropes. Analytical calculation methods are not suitable for the design of such structures. The method of verification of the design of an artificial shaft bottom made of ropes is the use of computer simulation tools. The article presents an innovative solution for the design of a steel rope artificial shaft bollom and a method for its verification. The verification was conducted by LS-DYNA crash test.