PESA ACT/NSW June Technical Talk

Recent Advances in Faulting and Folding in the NSW Coal Fields: Implications and Observations on Fault Hydrogeology

Understanding the impact of subsurface developments on groundwater is one of the key uncertainties for many resource projects. It is common for opponents to invoke faults as an existential threat to aquifers and groundwater systems.

While minor faulting is common within a development, the resource is generally relatively unfaulted and may be constrained by faults. Generally, groundwater models used to support environmental impact statements cover an area wider than the development and often include faults.

A simple set of workflows and schemas will be presented that can be used to characterise and understand the kinematics of faulting geologically. The hydrogeologic understanding of faults is intimately related to how they crosscut and displace aquitards, aquifers, and groundwater resources. These workflows will be illustrated using case studies from the Sydney and Gunnedah basins.

Particular care must be taken when reviewing data and drawing inferences. Sound geological data and principles must be used to parameterise the hydrogeology of faults. A relatively small amount of work done early, with the appropriate representation of results, will ease future developments and expansion.