❓ A parliamentary question regarding BGC's open-cut mining operation's impact on the Wooroloo Brook tributaries and groundwater quality, with the Minister's response addressing concerns about water source contamination and salinity.
AnsweredQoN 1353Legislative Council
QuestionView source ↗
Bgc (australia) Pty Ltd , OPEN-CUT MINING OPERATION 1353. Hon DEE MARGETTS to the minister representing the Minister for the Environment and Heritage: I refer to the previous questions and answers on 9 April 2002, 17 April 2002 and 18 April 2002 - questions without notice 1236, 1303 and 1318 - on the major open-cut mining operation for granite extraction operated by BGC (Australia) Pty Ltd at The Lakes, about 50 kilometres east of Perth. (1) Given that a map provided with the soil conservation notice issued by the Commissioner of Soil and Land Conservation to BGC (Australia) Pty Ltd on 25 January 2002 clearly shows that the existing mining operation straddles two tributaries of the Wooroloo Brook and the open-cut mine has mined out one of the tributaries, can the minister explain why she said that the mining operation is located between two upper tributaries of the Wooroloo Brook? (2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS
AnswerView source ↗
(1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
Bgc (australia) Pty Ltd , OPEN-CUT MINING OPERATION
I refer to the previous questions and answers on 9 April 2002, 17 April 2002 and 18 April 2002 - questions without notice 1236, 1303 and 1318 - on the major open-cut mining operation for granite extraction operated by BGC (Australia) Pty Ltd at The Lakes, about 50 kilometres east of Perth. (1) Given that a map provided with the soil conservation notice issued by the Commissioner of Soil and Land Conservation to BGC (Australia) Pty Ltd on 25 January 2002 clearly shows that the existing mining operation straddles two tributaries of the Wooroloo Brook and the open-cut mine has mined out one of the tributaries, can the minister explain why she said that the mining operation is located between two upper tributaries of the Wooroloo Brook? (2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(1) Given that a map provided with the soil conservation notice issued by the Commissioner of Soil and Land Conservation to BGC (Australia) Pty Ltd on 25 January 2002 clearly shows that the existing mining operation straddles two tributaries of the Wooroloo Brook and the open-cut mine has mined out one of the tributaries, can the minister explain why she said that the mining operation is located between two upper tributaries of the Wooroloo Brook? (2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
Bgc (australia) Pty Ltd , OPEN-CUT MINING OPERATION
I refer to the previous questions and answers on 9 April 2002, 17 April 2002 and 18 April 2002 - questions without notice 1236, 1303 and 1318 - on the major open-cut mining operation for granite extraction operated by BGC (Australia) Pty Ltd at The Lakes, about 50 kilometres east of Perth. (1) Given that a map provided with the soil conservation notice issued by the Commissioner of Soil and Land Conservation to BGC (Australia) Pty Ltd on 25 January 2002 clearly shows that the existing mining operation straddles two tributaries of the Wooroloo Brook and the open-cut mine has mined out one of the tributaries, can the minister explain why she said that the mining operation is located between two upper tributaries of the Wooroloo Brook? (2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(1) Given that a map provided with the soil conservation notice issued by the Commissioner of Soil and Land Conservation to BGC (Australia) Pty Ltd on 25 January 2002 clearly shows that the existing mining operation straddles two tributaries of the Wooroloo Brook and the open-cut mine has mined out one of the tributaries, can the minister explain why she said that the mining operation is located between two upper tributaries of the Wooroloo Brook? (2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(2) Given that there are photographs that clearly show the fractures in the open-cut mine have water flowing through them into the mine, so that pumping is necessary to allow work on the lower mine levels, why does the minister suggest that when this mine ultimately fills with water and evaporation generates salinity, that salty water will not then flow into the ground water system of the mined-out tributary? (3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(3) Given that the ground water entering the open-cut granite mine is of potable quality, being less than 500 milliSiemens per metre, and that this water is the feed stock of the proposed public drinking water source in the Water Corporation’s Perth water future strategy, why does the minister suggest that this water is brackish and why is nothing being done to prevent further deterioration of this water source? (4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(4) How does the minister defend turning a current potable ground water system saline in this way? Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
Hon TOM STEPHENS replied: (1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(1) The Minister for the Environment and Heritage has been advised by the Water and Rivers Commission that, in indicating the mining operation was located between two tributaries, it was recognised that mining could have intersected one of the tributaries. (2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(2) While the fractures seen in the photographs are open and yielding water, at depth it is common for these fractures to close up with their transmitting capacity to be reduced significantly. It is unlikely that there will be a significant flow of water into the ground water system from the open cut after the hydraulic gradient decreases on filling of the void. (3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(3) Ground water of 500 milliSiemens per metre is not potable, it is brackish to saline; that is, 2 750 milligrams of salt per litre. Government departments are working with catchment groups to address land and water degradation issues. (4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
(4) The potential future water source is a surface resource. Ground water quality in 21 bores within the general area varies between 220 and 14 300 milligrams per litre, only three of them being fresh.
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