Filling of abandoned coal mines located under the Ipswich Motorway, Queensland, Australia

The upgrade of one of Queensland's busiest road transport corridors, the Ipswich Motorway, between Dinmore and Goodna, by the Queensland Department of Transport and Main Roads (DTMR) involved re-aligning the motorway corridor over two separate abandoned coal mines and adjacent a third. During the preliminary site investigation and through the early stages of design, abandoned coal mines were discovered under sections of the footprint of the new motorway. Whilst there was some knowledge of the existence of these mines that had been operational from the mid 19th Century through until the late 1980s, details as to size, depth and accurate location were largely unknown. The DTMR formed Origin Alliance, an alliance made up of designers and constructors, to construct the motorway and to find solutions to the partial filling of these old abandoned coal mines where there was the potential to cause subsidence damage to the new motorway. Origin Alliance together with Keller Mine Fill, a specialist mine fill contractor, formed a sub alliance to tackle the task of accurately locating and target filling these mines so as to provide protection to the motorway asset against a future subsidence event.