An alternative underground hoisting system for Kahatagaha underground graphite mine, Sri Lanka- a case study

Abstract

Hoisting systems used in underground mines are essential for the transportation of equipment, personnel, mined ore and thus for the productivity of an underground mine. It consists of various components in which there are shear wheels, winches, wire ropes, lift cages, carriage boxes and electric motors. The safety and reliability of the hoist depends on its design, therefore proper and accurate design of a hoist is essential. A properly designed hoisting system also supports to increase underground productivity as well. Kahatagaha underground graphite mine is the deepest underground graphite mine in Sri Lanka, where the deepest level is 2080 feet below from the surface. The main lift operates up-to 1130 feet level from the surface and there are 5 inclined winzes equipped with pneumatic winches and hanging wooden boxes with the support of wire ropes for hoisting or lowering men and material as hoisting method from 1130 feet level to 2080 feet step by step between main underground levels. This hoisting method is very primitive and it has many bottlenecks when going to increase underground production, productivity and safety. This paper aims to provide a solution for current hoisting system & it`s issues mentioned above and presents the benefits of proposed hoisting system for Kahatagaha underground graphite mine. In fact, a cost-effective and safe hoisting system is a great support for any underground mine so that the proposed design would be a good alternative against the primitive system still in operation.