Collieries

Since the discovery of coal in the Collie Basin in the late 19th century, the resource has been almost continuously mined by underground and open cut methods resulting in a number of abandoned underground mine workings (the collieries). The footprint of these workings is extensive, with some of these now situated within the towns of Collie, Allanson, Collie Burn and Collie Cardiff.

A 1995 Minerals Research Institute of Western Australia Report identified 97 discontinuous subsidence locations above shallow abandoned underground mine workings, extending over a combined area of 72 ha. The 1995 report also states: “it is anticipated that failures will continue to occur in the foreseeable future”. ‘Hot ash’ (reactive carbonaceous shale) occurrences, which may represent an elevated fire risk, have also been reported in the region.

The Collieries project will extend across the Collie Basin identifying areas of high risk to the community and facilitate development of remediation approaches. New thermal camera technologies now available on drones provide a new stream of investigation, allowing for rapid interrogation of sites. Geotechnical, photographic and thermal data capture investigation will increase understanding of Collieries features susceptible to subsidence, as well as “hot ash” threat recognition.

Strategic objectives

1. To establish a consistent approach to assessing risks associated with ground subsidence and reactive carbonaceous shale in the Collie Basin, which will inform a prioritisation methodology to address risks to the community.
2. To develop and implement (based on risk to the community) appropriate rehabilitation strategies for the Collie Basin relating to ground subsidence and near surface reactive carbonaceous shale.