Hail Creek 2016 Low Wall Instability

Slope failure mechanism and recovery

Glen Guy

A significant low wall failure occurred in Ramp 3 North Strip 22 at the Hail Creek Coal Mine operation in Central Queensland on 31 October 2016 following the extraction of lower sequence Fort Cooper Coal (FC1 – FC4). The extent of the failure was approximately 1.2 kilometres in strike length with an arcuate back scarp at a maximum radius of 700 metres. The failure was interpreted to have occurred in two phases with the northern blocks failing initially before a re-mobilisation of the 2013 failure block occurred. Overall the failure has mobilised approximately 35 million bulk cubic metres of spoil down dip in a north easterly direction and resulted in up to 60 m of floor heave.

An extensive investigation was undertaken to determine the possible failure mechanism that instigated the failure. This renewed knowledge was then applied to the development of a recovery and monitoring plan for the strip so that mining could continue in the area. Knowledge acquired from the failure and recovery has then been applied to the development of a revised mining method for the area as well as other areas on-site. This presentation summarises the investigation and its findings, and discusses the recovery of the area following the instability.

About the speaker

Glen GuyPrincipal Mining Consultant & Director, Encompass Mining

Glen Guy is a Principal Mining Consultant and Director at Encompass Mining a multi-disciplinary mining consultancy based in Brisbane. Glen has over 20 years’ experience in the mining and exploration industry working on projects in New Zealand, Indonesia, Mongolia and Africa and has previously headed up the Rio Tinto Coal geotechnical department.

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