Geotechnical stability assessment of the Mount Morgan fireclay caverns

Brett Taylor and Patrick MacGregor

Abstract

This paper describes a qualitative geotechnical risk assessment of the stability of the Fireclay Caverns at the Mount Morgan Mine, located about 25 km south west of Rockhampton and comments on methods to manage and reduce geotechnical risk related to the caverns and nearby associated excavations.

Due to the discovery of dinosaur footprints in the roof of the caverns, the Department of Natural Resources and Mines (NR&M) propose developing tourism in the area by expanding visits to the caverns. Currently approximately 7,000 tourists visit the caverns per year.

The aim of the risk assessment was to assess the geotechnical stability of the fireclay caverns for the installation of boardwalks and staircases to provide access for tourism and as a guide to the interpretation, planning and long term management of the site to view dinosaur footprints expressed as impressions in the cavern roofs.

It was recognised that near the dinosaur footprints, subject to the stability hazard, the support of roof and walls using rock bolts or shotcrete would be regarded as a last resort.