❓ (a) can the Minister explain why the Department of Environment and Conservation (DEC) is not able to confirm that a permeability rate of 10-9 metres per second equates in a scientific sense to a water
AnsweredQoN 2959Legislative Assembly
QuestionView source ↗
(a) can the Minister explain why the Department of Environment and Conservation (DEC) is not able to confirm that a permeability rate of 10-9 metres per second equates in a scientific sense to a water seepage rate of about three centimeters per year which the DEC regards as being impervious for their purpose; and
(i) if no to (a), why not;
(b) can the Minister explain more precisely what effectively restricts seepage means in terms of the distance that seepage will travel with a permeability of 10-9 metres per second; and
(i) if no to (b), why not; and
(c) does the Minister support the DEC with its use of resources permitting the operator of the tailings dam to stress and kill vegetation causing pollution in the period from 1989 through to 1999 without taking strong enforcement action or prosecution action; and:
(i) if no to (c), then why not; and
(ii) if yes to (c), why?
(i) if no to (a), why not;
(b) can the Minister explain more precisely what effectively restricts seepage means in terms of the distance that seepage will travel with a permeability of 10-9 metres per second; and
(i) if no to (b), why not; and
(c) does the Minister support the DEC with its use of resources permitting the operator of the tailings dam to stress and kill vegetation causing pollution in the period from 1989 through to 1999 without taking strong enforcement action or prosecution action; and:
(i) if no to (c), then why not; and
(ii) if yes to (c), why?
AnswerView source ↗
Answered
25 February 2008
Responded by
Minister for the Environment
Response time
88 days
(a) The Department of Environment and Conservation has advised me that seepage rates from tailings storage facilities are variable and dependent on the total area of the facility, location and area of supernatant (liquid on top of the facility), permeability of the underlying material and recovery systems underneath and adjacent to the facility.
While a permeability of 10
-9
metres per second is considered impervious and is used to inform the design criteria, the actual permeability may vary after construction of the facility due to variation in the site characteristics.
(b) A permeability value of 10
-9
metres per second for a tailings storage facility is considered to be an extremely low and would restrict seepage. There are other factors however, as outlined in the answer to (a), which will affect seepage rates and volumes.
(c) Further to the answer to Question on Notice 1726 on 27 February 2007 by the then Minister for the Environment, I also do not support the use of Department of Environment and Conservation resources to locate and retrieve the files relating to that period of time.
The period in question is over eight years ago (1989-1999), and there is no evidence to suggest that vegetation is currently under stress or dying as a result of this facility.
Notice: This document is created or edited using unregistered or evaluation copy of rtLib valid for testing or development purposes only. To use it for productive or any other purposes please register it. You may purchase the license on
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While a permeability of 10
-9
metres per second is considered impervious and is used to inform the design criteria, the actual permeability may vary after construction of the facility due to variation in the site characteristics.
(b) A permeability value of 10
-9
metres per second for a tailings storage facility is considered to be an extremely low and would restrict seepage. There are other factors however, as outlined in the answer to (a), which will affect seepage rates and volumes.
(c) Further to the answer to Question on Notice 1726 on 27 February 2007 by the then Minister for the Environment, I also do not support the use of Department of Environment and Conservation resources to locate and retrieve the files relating to that period of time.
The period in question is over eight years ago (1989-1999), and there is no evidence to suggest that vegetation is currently under stress or dying as a result of this facility.
Notice: This document is created or edited using unregistered or evaluation copy of rtLib valid for testing or development purposes only. To use it for productive or any other purposes please register it. You may purchase the license on
http://www.rtlib.com
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