∕ ∕ ∕ ∕ ∕ ∕ ∕ ∕
Farm supply/use;
Stock water;
Human Consumer; Primary recreation; Secondary recreation;
Visual recreation; Drinking water; Industrial use; and
∕ Cultural and spiritual values. The Dee River is classified as highly disturbed from the Mount Morgan Mine to the confluence of the Don River. ARD is the key environmental concern at the mine site, posing a significant adverse risk to downstream catchments, namely the Dee, Don and Dawson rivers. ARD is caused by oxidised sulphide minerals in rocks and soils being mobilised by water moving over or through the sulphide minerals (Unger et al., 2003). This sulphidic waste material was dumped across a large area, including the slopes of relatively steep hills in the upper reaches of the Dee River catchment – factors which have facilitated its oxidisation and transport offsite. Sulphide minerals have been exposed to weathering for more than 100 years in some parts of the mine. Inadequate past mine management practices have left the Dee River in a poor state, where pH is as low as 2.8. High metal concentrations have been recorded in the Dee River next to the mine site during periods of low flow (Wels et al., 2007). While there is no recent evidence of acidic flows extending beyond the Dee River catchment into the Don, Dawson or Fitzroy rivers, there are anecdotal reports of acidic flows extending into the Dawson River when the mine was still working (GreenGold, 2021). River water quality monitoring indicates impacts from the Mount Morgan mine site are most prevalent in the first 20 km downstream (AARC, 2017a). The diversity of species in this section of the river is greatly reduced, however some species do exist. The water quality in the Dee River continues to improve with distance downstream as it is diluted by other freshwater catchment inflows. Although contaminated water seepage from the Mount Morgan Mine has a high level of sulphates (salts), the water quality at the lower end of the Dee River is suitable for irrigation and livestock. The water quality in the Dee River improves with distance downstream as it is diluted by large freshwater inputs further down the catchment. Water quality at Duaringa (140 km downstream of Mount Morgan) is suitable for potable use (GreenGold, 2021). The DSITI Guidelines for draft environmental values and Water quality guidelines for Fitzroy Basin fresh, estuarine and marine waters, including Keppel Bay (Newham et al. 2017) identify the Dee River as a highly disturbed ecosystem with modified environmental values and water quality objectives. Contaminated water seepage and runoff from the Mount Morgan Mine is currently managed by the State via the seepage interception system. While this has reduced contamination loads, the system cannot collect all contaminated water and water quality values in the Dee River remain adversely affected. The effects of this can be observed in monitoring data downstream from the Mount Morgan Mine in the Dee River. Due to impacts from the Mount Morgan Mine, water in the Dee River is not suitable for drinking or recreation, such as swimming or fishing. The DNRMMRRD have placed signage at all crossings along the Dee River advising no drinking, no swimming and no recreational activities. No wetlands of international or national importance, or high ecological value wetlands were identified within or proximal to the Project area during desktop assessments.
Project number: 25B061
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