Analysis of options of production and access ways in underground mines.

Abstract

This article aims to review the issues to be considered in choosing primary access and transportation options for underground mines. The main accesses to underground orebodies are declines or vertical shafts. They serve both as a way to transport ore or waste, and move people, equipment or supplies. In underground mines, the ore transport option significantly affects the productivity and profitability of the company. Then, choice of access is a way to reduce costs and improve production. This study is primarily based on some case studies of Brazilian, South African, Australian and Turkish mines, among others. Literature review shows that the depth at which shaft hoisting becomes a more economically attractive alternative to decline truck haulage is changing from being previously 350 m to present 1000 m, depending on the mining country and cultural underground mine development. For some of them the depth of 1000 m would be the threshold for use of the access by decline. The main criteria in determining access are depth, rate of production and mine life. In South Africa, mines reach depths greater than 3000 m and shaft access is more common. In Australia there are mines that use a ramp (decline) to a depth greater than 1000 m. In Brazil, underground mines are still shallow (depth up to 800 m) and feature short mine life and, most of them have chosen access by decline. Results of this study corroborate the statement that decline is ideal for shallow mines and low production rates and that shaft is for deep mines, high production rate and long mine life.