Leigh Creek Copper Mine

21 Jul 2010 questionsarchive

I seek leave to make an explanation before directing a question to the Minister for Mineral Resources Development about the Leigh Creek Copper Mine.

The Hon. J.M.A. LENSINK: With respect to the old Leigh Creek Copper Mine, which is currently under acquisition by Phoenix Copper and which has been investigated in the past under previous tenancy, action has been sought by the Copley District Progress Association. Previous owners of that particular lease set up an opportunistic venture south-east of Copley near Leigh creek in 2006. As I understand it, the mine currently stands dormant. However, there has been a one in 100 rain event in the past six months, which has resulted in acid leachate spilling over the heaped crushed ore.

The local community is very concerned that this leachate has flowed into the watercourse. I understand that PIRSA has undertaken some soil sampling which shows elevated levels in the creek. However, my understanding from the progress association is that PIRSA is of the opinion that compliance issues at the mine are minor. My questions to the minister are:

1. Can he outline what visits PIRSA has made to this particular site and what investigations it has undertaken?

2. With respect to the soil and water testing that has been carried out on-site following this rain event, is the minister concerned with any levels of particular chemicals and which chemicals would they be?

3. Can the minister advise the current status of that particular site?

The Hon. P. HOLLOWAY (Minister for Mineral Resources Development, Minister for Urban Development and Planning, Minister for Industrial Relations, Minister Assisting the Premier in Public Sector Management) (14:31): I thank the honourable member for her question. I understand that the Hon. Mr Parnell also requested some information. By now he should have a significant bulk of information under FOI in relation to those events, which includes all the detailed reports, as I understand it.

As the honourable member said in her question, Phoenix Copper announced on 8 July its purchase of the Leigh Creek Copper Mine, which is likely to be finalised in late July 2010 following shareholder approval. So, we are talking about events that happened prior to that.

I just make the comment that I think that the takeover of this operation by a more substantial company will be a good thing. Leigh Creek and districts (in which the Mountain of Light copper mine is located) had a high rainfall event commencing on Thursday 8 April 2010 which totalled 92.2 mm over a two-day period.

As a result of this event, the copper leachate solution in the heaped leach pads at the Mountain of Light mine overflowed the collection drains and then flowed into the stormwater silt retention dam. This dam is located on the lowest point of the lease, near the lease boundary adjacent to an ephemeral creek. It is designed to collect stormwater from the site to settle out silt before any water is released to the creek.

The rainfall event resulted in some copper leachate solution flowing directly into the silt retention dam, which then overflowed into the adjacent ephemeral creek. The creek was visibly contaminated with a diluted copper leachate solution for a distance of approximately 500 metres downstream from the mine site.

A subsequent rainfall event on 19 April removed any visible signs of the copper leachate from the creek. The operators of the mine notified PIRSA by phone of the spill on Sunday 11 April 2010. This was followed up with a formal notification by email on Monday 12 April at 3.30pm from the tenement holder, Leigh Creek Copper Mine.

At the time of the notification it was indicated that it was not possible to commence immediately remediation activities due to the inaccessibility of vehicles to the site as a result of the rain. PIRSA dispatched two officers to the site to undertake an inspection on Wednesday 14 April.

Following the inspection, PIRSA met with the EPA on 16 April to discuss the spill. PIRSA is the lead agency, which will liaise with both the EPA and the Department of Water, Land and Biodiversity Conservation, to ensure the most appropriate and timely remediation of the creek contamination without causing further damage to the creek system.

On 16 April, PIRSA issued a formal notification letter to the tenement holder, which is the Leigh Creek Copper Mine (LCCM). The notification letter instructed LCCM Limited to undertake an internal investigation into the incident, to provide PIRSA with a site remediation plan and to commence site remediation by 23 April 2010. PIRSA also instructed the LCCM not to commence any remedial activities in the creek system until further instructions from PIRSA were provided.

LCCM provided a site remediation plan on 23 April which included the immediate rectification of the issues that cause the overflow and seeking engineering consultancy advice to implement improvements as necessary to ensure that future significant rainfall events are accommodated properly. LCCM has committed to the completion of the immediate rectification works by 14 May and any resultant works from the consultancy advice by 30 June.

On 28 April 2010 PIRSA was contacted by a member of the Copley and Districts Progress Association who expressed concern that the Copley Dams and some nearby borrow pits that are currently filled with water may have been contaminated with copper and arsenic from the Mountain of Light Mine overflow. These dams are believed to be used for recreational purposes.

In close conjunction with the EPA, PIRSA responded by despatching an officer to collect water and soil samples from relevant locations, including the Copley Dam, on Friday 30 April. He was accompanied by a member of the Copley and Districts Progress Association during the collection process. Analysis of the water samples by the EPA indicated that the copper and arsenic concentrations were well within the guideline requirements for primary recreational contact such as swimming. The EPA directly contacted the Copley and Districts Progress Association on Friday 7 May with the results of the analysis.

The soil samples taken in the creek bed adjacent to the mine site returned slightly elevated copper concentrations that were still within the guideline requirements for standard recreation use. The results of the soil sample analysis were communicated to the Copley and Districts Progress Association by PIRSA on 15 June. On 15 June two PIRSA officers inspected the site remediation works. The remediation works appeared to have been completed to plan and engineering sign-off was requested before recommencing operations. The PIRSA officers also collected a series of soil samples in the creek bed with the aim of providing sufficient information about the nature of the copper contamination such that an appropriate remediation plan for the creek bed could be devised. Sample results and a draft remediation plan are expected by 23 July.

PIRSA, together with the EPA and the Department of Water, Land and Biodiversity Conservation, will continue to closely monitor the Mountain of Light Mine to ensure that all remediation activities are completed to a satisfactory level. That was the action that was taken following the April high rainfall event.

The only other point I should make is that this particular operation at the Mountain of Light copper mine comprises shallow open pit mining of non-sulphide copper ores and adjacent dilute heap leaching. The site has not been actively mined since early 2009 due to low copper prices; however, operations are due to recommence in 2010.

In fact, as I said, it had not been operating as a mine at the time of the event and that is why the takeover of this operation by Phoenix Copper, should it be approved by shareholders, would be a good thing. The original mining lease was originally granted in 1987 and most recently renewed in 2008. I think that should provide all of the answers to the honourable member's question.