Grosvenor Project EIS (QLD)

Alluvium completed a Surface Water Impact Assessment for Anglo American Metallurgical Coal as part of the Environment Impact Statement (EIS) for the Grosvenor underground coal mine near the central Queensland township of Moranbah. The EIS received approval from Queensland’s Department of Environment and Resource Management (DERM) in September 2011.

The assessment methodology followed that developed in the Isaac River Cumulative Impact Assessment of Mine Developments which has since been adopted by DERM as an industry guideline (Watercourse Subsidence – Central Queensland Mining Industry v1.0, Draft, 2011). Surface Water components included geomorphic assessment of watercourses across the site, determination of their environmental values and baseline condition monitoring. Predictions of geomorphic response following mining related subsidence were then made, informed by sediment transport projections and hydraulic modeling of pre and post subsidence scenarios.

The extent of pre-subsidence and post-subsidence ponding on the floodplain was mapped and quantified to determine the impacts to overland flow and also to assist with ecology assessments. The impact of the Project on downstream users was quantified for the 100 year and 1000 year ARI flood events by comparison of flood hydrographs pre and post development.