Uncertainty about the clean-up of Ranger uranium mine in Australia’s Northern Territory

Environment and Communications Legislation Committee 23/05/2017 Estimates
ENVIRONMENT AND ENERGY PORTFOLIO
Clean Energy Regulator

Full Transcript: http://parlinfo.aph.gov.au/parlInfo/search/display/display.w3p;adv=yes;orderBy=customrank;page=0;query=Dataset%3AcomSen,estimate%20Dataset_Phrase%3A%22estimate%22%20CommitteeName_Phrase%3A%22environment%20and%20communications%20legislation%20committee%22%20Questioner_Phrase%3A%22ludlam,%20sen%20scott%22;rec=5;resCount=Default

CHAIR: I welcome the Office of the Supervising Scientist.

Senator LUDLAM: I understand that ERA is in the process of starting to get on with closing the Ranger uranium mine in Kakadu and have notified stakeholders—presumably including yourselves—that they are intending to vary the way that they are depositing the tailings back into pit 3, and that they are proposing to change from an aerial tailings deposition to subaqueous deposition. For the non-specialists, could you describe maybe in plain English the difference in technique they are proposing.

Mr Tayler : The previous tailings deposition methodology had tailings being dredged from the tailings dam and tailings coming from the mill being deposited onto a beach, essentially. The new methodology that ERA is proposing involves depositing tailings through water; hence the subaqueous versus subaerial. Essentially, it was being put onto a tailings beach; the new method will be depositing it through the water column itself.

Senator LUDLAM: Is the decommissioning of the mine being treated as a nuclear action under the EPBC Act?

Mr Tayler : No.

Senator LUDLAM: Can you describe for us why not?

Mr Tayler : I would prefer that questions specific to the EPBC Act were directed to the Environmental Standards Division, or we could take it on notice if that is okay.

Senator LUDLAM: I think that is fair enough. If you can take it on notice, but I guess the answer is not going to come from you, is it? I think we have already let these people go.

Mr Tayler : Yes, it is a legal point, and I would not want to comment on that in case I got it wrong.

Senator LUDLAM: That is fine. I understand there is an interception trench, which intersects the saline plume coming out from under the tailings storage facility. We have been asking your predecessors in this office for years about this. My understanding is that ERA is currently monitoring that plume of saline water. There is a certain amount of dewatering that is being done. How long is it expected that monitoring and dewatering operations would continue beyond 2020?

Mr Tayler : In relation to the seepage—

Senator LUDLAM: In 2026, I beg your pardon. In relation to the monitoring of that saline plume and the dewatering.

Mr Tayler : Specifically related to the tailings dam?

Senator LUDLAM: Yes.

Mr Tayler : That is not information that we currently have. It is on ERA’s work program to conduct some detailed groundwater modelling of the TSF footprint. The TSF will not be decommissioned for several years yet, so I could not give you a specific answer to that question at this time.

Senator LUDLAM: When is the expected decommissioning date for the tailings storage facility?

Mr Tayler : I would have to take that on notice for the exact date. I believe it was towards the end of the rehabilitation process, which would put it in the 2024-25 period, but I will confirm that for you.

Senator LUDLAM: I will tell you what the purpose of these questions is: we have a plume of saline water that ERA was a bit reluctant to concede even existed, seeping out from under the dam, carrying goodness knows what other processed chemicals and radionuclides and whatever with it. We have the company with interception trenches, possibly bores, trying to get a sense of how much water is falling out the bottom of the TSF. We have an interception trench which is allowing them to remove some of that water and presumably process it and clean it up. That is a very active process of maintenance. How long is it anticipated to last?

Mr Tayler : Yes, I understand the question. At this stage, I do not have sufficient information to answer that question.

Senator LUDLAM: In terms of a yes/no. Is that because you do not have it at the table or you do not think that knowledge exists at this time?

Mr Tayler : I do not think that knowledge exists at this time. We need ERA to complete some proposed groundwater modelling. That will model the movement of that plume. That will give some indication of how long that plume will take to move, how long it will take to dilute and what management, if any management, will be required. That work has not yet been undertaken.

Senator LUDLAM: It is 2017. How does the ERA not know that already? I have been asking about this for about eight years, and this was an issue way before I came along.

Mr Tayler : Operationally, I think the issue has been quite well managed. We can provide an update on that if that would be helpful. From a long-term closure sense, the focus has been on looking at the groundwater impacts from the pits. Further work is still required on quantifying exactly what is beneath the TSF and what that may look like in the future.

Senator LUDLAM: So they still do not really know what is coming out from underneath the dam?

Mr Tayler : In an operational sense, we know very well exactly what is moving now. How that will behave over the long term into the future is not yet quantified.

Senator LUDLAM: Could you provide us with an estimate of how much water is seeping out from under the TSF every year? We have had order of magnitude estimates going back a couple of years.

Mr Tayler : For the whole dam? I would have to take that on notice.

Senator LUDLAM: Thank you. What I am trying to find out is whether that process is still going to be underway beyond 2026 or if it is within the company’s work plan that it is all well and truly done.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


%d bloggers like this: