❓ A WA parliamentary question addresses concerns about acid sulphate soils and potential environmental impacts from mineral sands mining, specifically Jangardup South and the decommissioning of Beenup mine, including potential leaching of acid sulphate water.
AnsweredQoN 322Legislative Council
QuestionView source ↗
I refer to the Jangardup South mineral sands mine proposed by Cable Sands (WA) Pty Ltd -
(1) Has soil sampling been carried out at or near the proposed Jangardup South mineral sands mine?
(2) If so, has sampling uncovered any acid sulphate soils and if so at what depth was it found?
(3) What are the effects of acid sulphates on aquatic environments?
(4) At what stage is the Environmental Protection Authority assessment of this project?
(5) At what stage is the decommissioning of the Beenup Mineral Sands mine?
(6) Is the Minister aware of any leaking of acid sulphate water from the tailing dams and/or dredge pond at the former Beenup mine and if so how extensive is this leaching?
(1) Has soil sampling been carried out at or near the proposed Jangardup South mineral sands mine?
(2) If so, has sampling uncovered any acid sulphate soils and if so at what depth was it found?
(3) What are the effects of acid sulphates on aquatic environments?
(4) At what stage is the Environmental Protection Authority assessment of this project?
(5) At what stage is the decommissioning of the Beenup Mineral Sands mine?
(6) Is the Minister aware of any leaking of acid sulphate water from the tailing dams and/or dredge pond at the former Beenup mine and if so how extensive is this leaching?
AnswerView source ↗
Answered
12 December 2001
Responded by
Minister for Housing and Works representing the Minister for the Environment and Heritage
Response time
29 days
(5) BHP Billiton is implementing the approved Beenup Mine Closure Plan. Works within the plan are due for completion in mid 2003. Works are on track to develop the mining voids into a series of wetlands and reinstate surface flows through the site by the start of winter 2002. Further, BHP Billiton is undertaking predictive modelling work and testing to assess the likely impact on low pH groundwater which resulted from trial mining at the site. (6) Because the dredge pond and tailings facilities were not lined, it is likely that some water from these facilities leached into the adjacent groundwater. However due to the very low hydraulic conductivity of the area, it is predicted that such seepage was minimal. This has been confirmed by groundwater testing down hydraulic gradient of the mine path and around the tailings facilities, which has not detected significant impacts. As a precautionary measure, BHP Billiton have increased the pH within the dredge pond and tailings facilities to neutral (through the use of lime sands), to offset any potential impact of seepage on the groundwater in the area.
(6) Because the dredge pond and tailings facilities were not lined, it is likely that some water from these facilities leached into the adjacent groundwater. However due to the very low hydraulic conductivity of the area, it is predicted that such seepage was minimal. This has been confirmed by groundwater testing down hydraulic gradient of the mine path and around the tailings facilities, which has not detected significant impacts. As a precautionary measure, BHP Billiton have increased the pH within the dredge pond and tailings facilities to neutral (through the use of lime sands), to offset any potential impact of seepage on the groundwater in the area.
(6) Because the dredge pond and tailings facilities were not lined, it is likely that some water from these facilities leached into the adjacent groundwater. However due to the very low hydraulic conductivity of the area, it is predicted that such seepage was minimal. This has been confirmed by groundwater testing down hydraulic gradient of the mine path and around the tailings facilities, which has not detected significant impacts. As a precautionary measure, BHP Billiton have increased the pH within the dredge pond and tailings facilities to neutral (through the use of lime sands), to offset any potential impact of seepage on the groundwater in the area.
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