Interim Independent Expert Scientific Committee on Coal Seam gas and Coal Mining

Hydrology: changes in dynamics and aquifer interconnectivity

Coal seam gas extraction may increase the risk of interconnectivity between groundwater aquifers with potential consequences for fresh water aquifers both in terms of quantity and quality. Changing interconnectivity between aquifers can also have implications for surface water resources. Large coal mines, on the other hand, may disrupt surface flow through river diversions and flood protection works, and dewatering of the mine can also disrupt groundwater flow patterns.

Projects commissioned to date include:

Project title Project description
Background review -
bore integrity

The review captures the state of knowledge on bore integrity issues as they relate to coal seam gas extraction in Australia. The review examines issues associated with bore construction, integrity, monitoring and reporting, decommissioning, and legacy issues. The focus of the review is the Australian coal seam gas context, but a summary and synthesis of case histories from overseas and within other industry sectors is provided.

Background review -
subsidence from coal mining activities

The review captures what is currently known about predicting, monitoring, assessing and remediating subsidence and other movement-related impacts associated with coal mining activities, including:

Background review -
subsidence from coal seam gas extraction in Australia

The review captures the state of knowledge on the water-related impacts of subsidence and other ground-related movements as a result of coal seam gas extraction, including:

  • the different causes of subsidence
  • technology and tools for monitoring, measuring and assessing the extent of subsidence models to predict the scale and extent of subsidence
  • remediation options.
Background review -
aquifer connectivity within the Great Artesian Basin, and the Surat, Bowen and Galilee Basins

The review captures the state of knowledge on aquifer connectivity, particularly within the Great Artesian Basin (GAB), and the Surat, Bowen and Galilee (geological) Basins, including:

Monitoring and management of bore integrity This project seeks to reduce the potential risk of aquifer leakage by improving the integrity and monitoring of existing and discontinued coal seam gas and agricultural bores. This will be achieved through the identification of priority areas for investigating bore integrity; the identification of priority bores requiring examination; and an evaluation of bore monitoring and investigation approaches.
Monitoring and management of subsidence induced by longwall coal mining This project aims to improve understanding of the critical issue of subsidence induced by longwall coal mining, and its consequent effects on water systems and on land use.
Monitoring and management of subsidence induced by coal seam gas extraction This project aims to improve understanding of the critical issue of subsidence induced by coal seam gas extraction, and its consequent effects on water systems and on land use.
Comparison of groundwater modelling approaches This project will research existing groundwater models and the capacity of the models to predict impacts of coal seam gas production.
Regional hydrogeological characterisation studies in four coal basins in Queensland, South Australia and Victoria Multidisciplinary characterisation of the detailed geology and hydrostratigraphy of the Laura, Maryborough, Otway and St Vincent Basins.