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Monday, 5 March 1984
Page: 361

Senator WALSH —by leave-In response to a question from Senator Reynolds on 1 March in relation to the release of contaminated water from the Mary Kathleen uranium mine site I indicated that the release was accidental and had occurred while liquid was being siphoned to a lower pond to avoid possible overflow from an upper pond during extraordinarily heavy rain. That advice was based on a briefing earlier provided to me by my Department which in turn was based on information supplied from the Queensland department. I table a document prepared by Mr McGregor, First Assistant Secretary in the Uranium and General Division of the Department of Resources and Energy, which is his note for file on that question. My Department has now drawn to my attention that it was misinformed on the nature of the incident. I seek leave to incorporate in Hansard a background information statement dated 27 February 1984 by Mary Kathleen Uranium Ltd.

Leave granted.

The document read as follows-


Release of Evaporation Pond Liquid at Mary Kathleen

Since the commencement of operations at Mary Kathleen in 1958 the process liquids have been retained and evaporated in large ponds. When operations ceased late in 1982, work started on a 2 to 3 year programme aimed at drying out the ponds, cleaning up the area and revegetating it.

Operation of the evaporation ponds at this stage in the programme involves the pumping of liquid between ponds to maintain optimum evaporation conditions over the area.

There are two main evaporation ponds and several very small subsidiary ponds.

Prior to the commencement of the monsoonal rainfall, the larger main pond was almost empty in preparation for the next phase of the rehabilitation programme. The other main pond was only 70 per cent full.

Rain began on the afternoon of Monday February 13th and continued until Friday 17th February. A total of 242mm (approx. 10 inches) fell during this period. In anticipation of larger rainwater flows, extra freeboard was created in all of the ponds by transferring liquid into the larger main pond. However, rainwater filled the particular subsidiary pond faster than anticipated, because the liquid level had not been adequately adjusted.

In order to prevent pond liquid from overflowing approximately 1 megalitre of liquid was released in a controlled manner, by syphoning it into Cameron Creek.

The release was stopped immediately the level of liquid in the pond was stabilised.

The liquid in the evaporation ponds is over 90 percent water, with less than 10 percent of solids in solution or suspension. The bulk of these solids are manganese and iron salts. Other elements or salts contained in small proportions include:







The salt content and radioactivity level of the liquid put it above drinking water levels. The liquid is acidic and most of the dissolved salts in the liquid only remain in solution at relatively high levels of acidity. When the acidity of the liquid is lowered (such as when the liquid is added to ordinary water with a more normal PH level) various salts precipitate out. This happened when the discharged liquid met the creek water. The dissolved salts therefore precipitated into the creek. These, together with material in suspension caused staining of the creek and left a residue on the creek bed.

It should be noted that, although the quality of the liquid in the pond was below potable standards, it was considerably diluted when it entered the creek. Extensive tests are being conducted to determine the exact composition of the creek water and the solids deposited on sections of the creek.

For information: Terry Ward, General Manager-MKU Telephone (077) 43 8311 A/ Hours (077) 43 2988.

Senator WALSH —The statement indicates that the controlled release of contaminated liquid into Cameron Creek took place. Neither I nor my Department was aware of this at the time I answered Senator Reynolds's question. I had been briefed on the basis of advice to my Department from a senior official of the Queensland Government that the release was accidental. Unfortunately that advice was incorrect. I add that I intend to take follow-up action, firstly, to determine the level of impurities in the water still in the pond in question, and, secondly, to determine what measures can be taken to ensure that there is no recurrence of this incident. I note again, as I noted when answering the question on 1 March, that those are matters which will have to be taken up with the Government of Queensland because it is responsible for the rehabilitation of the Mary Kathleen uranium mine site and not the Commonwealth Government.