ABSTRACT

Ground Support in Mining and Underground Construction-Villaescusa & Potvin (eds.) © 2004 Taylor & Francis Group, London, ISBN 90 5809 640 8

ABSTRACT: Recent underground mining of the Sons of Gwalia Mine at Leonora was carried out from 1999 to 2003. Many of the Sons of Gwalia Mine extensive old workings were unfilled from earlier underground operations, which led to relaxed and collapsed ground conditions, making mining particularly difficult. Due to the range of mining methods used, the low dip of stope walls as well as the need to “prefill” some existing voids, backfill was critical to controlling the rock mass response to mining and hence the success of the operation. The backfill system developed has needed to be flexible and cost effective, with minimal capital expenditure. After reviewing all backfill options, a cemented rockfill system using development mullock was selected. This paper will present the evolution of the backfill system at Sons of Gwalia, including the many challenges encountered, to produce a backfill product that accommodated the shallow dipping stope hanging walls, speed of fill requirements, varying consistency of waste rock supply and cost effectiveness.