Designing a more stable tunnel at PAARI mining syndicate

Abstract

High fracturing and faulting at Paari Mine syndicate have resulted in weak ground conditions making it difficult to conduct mining operations safely. The hanging walls and the side walls are covered with numerous faults and intersecting striking joints forming wedges which are extremely unstable. The project aims to solve the mines problem of tunnel subsidence. The work performed included studying the rock formations within the mine and determining their properties and response to excavations. The rock mass was then classified according to the rock mass rating and the rock quality index. Support design was done using guidelines according to rock mass rating tables. Ground support practices that are currently used at the mine and analysing vulnerabilities of the system were then studied and the use of systematic rock bolting, 2 meters long with a diameter of 24 mm fully grouted was proposed. In addition, we recommend that a spacing of 1 m to 1.5 m of the bolds should be used on the crown pillars as well the walls and that wire mesh should also be used as an additional support mechanism.