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 The Acid Lake Pictured below is a kilometre long and 15 metres deep. It is one of six lakes on this mine lease in Collinsville Queensland. (as of June 2004)

 Acid Mine Drainage (AMD) is a problem that is being faced world wide in coal producing areas. Councils interest in participating in an experiment in Collinsville may be a noble environmental step forward or a potential liability hazard. We try to find the answers.

 A  report by R. Norson, June 2004

A proposal from the Australian Coal Association Research Program (ACARP) was approved with little discussion at the council meeting in Collinsville on 16 June. The brief report outlined a plan to invite participation from council to supply sewerage waste, at council expense, to an acid lake on the mine site for the stated purpose of “remediation” or rehabilitation of the lake waters.

In these days of water shortages and concerns over waste disposal, such a proposal sounds good, and was no surprise to see approved.

In examining the proposal after the council meeting I came to some technical data that was beyond my understanding. To clarify the issue I directed fax copies of the proposal as presented to council to George Meyer. Mr. Meyer was an operator of a precious metal refinery and has extensive knowledge in chemistry and metallurgy. Upon reading the proposal, Mr Meyer contacted me to discuss the technical information. Mr. Meyer's first thoughts were “why is your council getting involved in this?” He stated his opinion that the council had little to gain in the proposal and could be subject to liabilities in the end. “To the best of my knowledge the mine is responsible entirely for the remediation of any damage to the environment. It appears to me that the council is paying for the privilege of assisting the mining company to clean up its problems and may inherit legal liability as the reward.” Mr. Meyer was also a mine operator for several years and has a good understanding of general mining laws and regulations, granting that recent changes to the structure of the EPA and the Department of Natural resources and mining have changed in the last 4 years. “Your council is about to import onto a mining lease, toxic material that may or may not be of benefit to anybody. It is clearly stated that the project is an experiment. If it works you might be alright but not necessarily. If the water is successfully treated and removed, the lake bottom may be a clean up problem” I asked if he was certain of the liability. “No,” he replied, “I'm not because of some legislative changes, however, under the act as it stood a few years ago I would call a liability issue probable and I would be surprised if the recent change in enforcement from mines to EPA would make that much difference. The point is that I do not see the benefit to the rate payers so why would you take any risk at all.”

In a phone conversation with Joel May, the environmental adviser with Xtrata, I asked what benefit the research would have for Bowen Shire. He stated that the benefit would be in the rehabilitation of the water and in finding an alternative in the disposal of the waste. I pointed out that I thought the water was already the sole responsibility of the mine and that the mine is required to do that anyway. He admitted that was true and reiterated the benefit of the disposal of the waste.

Reclaiming the water has to have benefit but for whom?

In the proposal presented to council it states that the end uses for the water “might include passive and active recreation, fishing, aquaculture, irrigated horticulture, conservation and garden reticulation……Further more the water may be useful within the mine for dust control or for use in the Power Station cooling.”

When asked about the possibility of aquaculture in particular, Mr. Meyer said that he thought the chance for that was “nil.” If dangerous metals such as lead and cadmium, that could be present, could be precipitated out of the solution, the oxygen levels would still be a problem, he said. I asked Joel May about this and he admitted that the proposed use of aquaculture in particular may be optimistic. When the use of dust control was mentioned he agreed that was a very realistic use. Mr. May went on to describe the benefit of not having to take water from the river to use for this purpose if the acid lakes could be lowered in acidity enough to use in stead.

It does appear that the most likely use for the water would be within the mine and that it should reduce demand on other sources.



 What exactly is wrong with the water?

The following is a brief report based on the examination of several web sites including the U.S. EPA and
Dr. Mark Lunds.
Often called Acid Mine Drainage (AMD) the waste water from coal mining operations is a world wide environmental problem. AMD is characterised as being acidic (low ph, 4 or under) and possibly with measurable amounts of metals such as cadmium, lead, copper, iron or others.. Areas with deposits of pyrite and sulphur, normal for a coal field such as Collinsville, tend to produce low ph (acid) and the pyrite releases metals as it weathers. The overburden and surrounding heaps might continue to produce traces of the materials from the leaching of water on its way into the lakes. In Collinsville this has been mitigated by the cutting of a ditch around the area of the lake that directs rainwater away from it. The amount of the metals in the water determines the risk. The investigation I have made suggests that Cadmium, for example, is dangerous. (see adjoining report) Mr. May said he considers the quantity of cadmium in the water at the Collinsville AMD lake to be very low, well within safe levels..

It is Black Water..light is absorbed within millimetres

The scale of the project seems large. Though Mr. May suggested they may reduce the size of the lake for the experiment. The depth is 15 metres. He reports that the waste is intended to be 1 metre thickon the bottom when completed. A yellowish residue traces the shore of the lake. It appears that the level of the lake is stable. The lake has no liner or means of sealing. Joel May informed me that the lake is on sandstone which he feels confident will retain the liquid. I consulted with George Meyer on the sandstone issue and he expressed concern for the material. He said that clay would have been far better. “Sandstone by nature is porous and may be heavily fractured which could allow a further capillary effect that could let the water leach out. I can not know that because I don't have all the information but I would be concerned. In worst case, the stable level of the lake may be because it has reached the level of the water table.

Studies available from other countries reveal the problem to be wide spread. Methods that have been tried include the dumping of hundreds of tonnes of lime, which was supposed to increase ph but failed in the New Zealand study I reviewed. That same study from the University of Otago's Department of Geology (see web site): also studied the remedial effect of wetlands adjacent to the lake. Their study found that time was the greatest factor. The longer the surrounding terrain was left undisturbed the better the ph. In time it seems that an AMD lake will probably “heal” but the length of time is long, decades rather than years.

Dr. Mark Lund, the project leader of the proposed experiment, states that there are other sources of organic matter besides sewerage that may be useful. They include mulch, sawdust, hay, wine lees, manures and even waste from aquaculture. He advises that consideration has to be given to end use and health and safety issues associated with some of the materials. (sourced from “Controlling acidity in
Flooded Collie coal voids- is it necessary and how can it be achieved?) The aim is to encourage biological processes found in normal lakes that will naturally adjust the ph. The nutrients from the organic matter may support kinds of bacteria that can have a positive effect.

I asked what method was normally used to deal with the AMD water. Mr. May said that they would transfer the water into an evaporation pool and the sludge would be put into a land fill.

How can Bowen Shire be indemnified against liability for contributing to this experiment? I asked Mr. May that question. “I would say that would be included in the third party agreement….that we could not go back on them.” Is that an existing or proposed document? “Its an existing form that you apply through the environmental Protection Agency I guess, Gary Martin (Bowen Shire manager for water and sewage) is probably better off talking to.” Mr May then mentioned the Collinsville golf Course receiving effluent as an example of the liability issue. It is true that the golf course does have a pond used for irrigation that receives liquid treated effluent. It is a small scale project and the water is treated with chlorine and electronic methods. I had a chat with a care taker there. Another difference is that the golf course doesn't have the metals or acid.

The biggest difference though, may be the legislation that applies. Mr May said that as far as the environmental legislation goes, the golf course and the mine are now “all under one umbrella.” While it does seem to be the case that the EPA now has jurisdiction over the lot, the legislation may still differenciate between a mine and a golf course. I contacted a senior official with the Department of Natural Resources and Mines, Mr Roger Billingham. His title is Chief Mines Inspector. Since the change in legislation that handed the environmental issues to the EPA, his primary responsibility is now safety and health. When I asked about the council's involvement in the mine site he stated that the council “…has no jurisdiction or authority on a mine lease.” When I asked if council may have a liability issue with the experiment, he stated “absolutely!” .

What did the EPA say about the liability issue?. I contacted Phil Jeston of the Townsville office of the EPA. The Collinsville operation is his area. He would not answer any question. As I was media he said he was required to hand me over to a “media adviser.” I was referred to the Brisbane office of Mr. Chris Dahl. He resonded sometime later;
“....Any action that successfully improves the quality of the water impacted by the mine would be welcomed by the EPA.” While we are grateful for the response, it does not address the issue of liability.

I called Joel May for a response on this issue of the porosity of the sandstone that the AMD Lake is in. He confirms that the nature of the lake bed is porous. The mine has sunk three bores within about 100 metres of the Lake for testing purposes. Lab reports are pending from samples taken. The Lake in its present location is approx. 5-6 years old