On 28 May Dayne Pratsky filmed this dramatic footage of gas bubbles which have appeared in four places over a five-kilometre stretch in the Condamine River near Chinchilla. As this Channel Ten item shows (both courtesy of gasileaks) Origin Energy were quick off the mark with calming words.
The company claims that such seepage has occurred naturally for at least 30 years, according to local knowledge. Drew Hutton from Lock the Gate says that local farmers have never heard of it. Dayne Pratsky told Fran Kelly that the landholder had been there 40 years and knew nothing of it. Another local had fished the hole for 60 years and had never seen anything like it. Among other problems Pratsky had seen in his local area was a crack in the ground which had opened up, leaking methane.
The State Minister quoted the Government CSG Enforcement Unit as saying it was all AOK. Pratsky reckons they call it the CSG Endorsement Unit and says they did their investigation from an office in Brisbane by ringing Origin Energy.
Gavin Mudd, an academic hydrogeologist from Monash University, said at The Conversation he would “find it hard to be convinced that CSG has nothing whatsoever to do with the gas bubbling away in the Condamine”. He wants hard data, not bland assurances.
Unfortunately that is where we are going to have to leave it for now, I think, until such data is generated, but we also need transparency and trust, which seem to be lacking at the moment.
Whatever the truth about this incident, I suspect that we are going to see more nasty surprises as the CSG industry proceeds. I’ll tell you why.
In my Crikey piece on underground aquifers, I looked at the work of hydrogeologist John Polglase, who stressed that large scale mapping cannot pick up fractures and fissures in aquitards which could provide pathways for interconnectivity between aquifers. All may be in order in a monitoring well, but all may not be in order 500 meters away.
Secondly, Mal Helmuth, in his preliminary risk assessment found that while some areas had a higher risk than others, in fact “the risk points were spatially heterogeneous, that is higher, medium and lower risk points were clustered together.”
Now look at how the Queensland Water Commission went about creating their model. The full report and an overview can be accessed from this page. There is a shorter summary at Beef Central and a longer account, giving the reaction of various groups, at Queensland Country Life (QCL).
The study area was 550 x 660 kilometres, giving an area of 363,000 square kilometres. In the model they created cells of 1.5km square. That gives you 161,333 cells. But data inputs came from just 1500 bores. The Regional Monitoring Network is going to consist of 498 wells on 142 strategically placed sites. 106 already exist, with 392 to be constructed. So the existing data is adequate in some places but inadequate in others.
I’m not suggesting that you need a bore in each cell. Rather I’m highlighting that what you get in this sort of exercise is a smoothed depiction of reality. This is exactly what Polglase was complaining about and what the report does not resolve in terms of the micro-geology relevant to the farm level.
Some progress has been made. With 19 layers in the model what emerges is a far better picture of how the sedimentary layers laid down over the last couple of hundred million years relate to each other. We now have a much more complicated ‘layered cake’ representation. This highlights the existence of sweet aquifers below the coal seams, whereas most earlier depictions only showed the usable aquifers above the coal seams.
But it is still a generalised, smoothed picture. I suspect we will learn just as much in the future from the instances where problems occur, providing they are treated seriously and studied.
John Hillier, in an article in the QCL (not online) said the the error bands in this kind of model are plus or minus 2 to 5 metres. This is especially important when you consider the Condamine Aquifer, where the trigger point to activate ‘make good’ measures is only two metres. I have to admit to being a bit shocked to read in the text how much we don’t know about the interconnectivity of the Walloon Coal Measures and the Condamine Aquifers, then read the confidence with which a 50cm impact is predicted, and then read the case for urgent further research.
It is also worrying to compare the conclusions of the QWC report with an Arrow EIS study, reported here by James Nason. The critical table cited by Nason is this one:
That comes from Chapter 28. The shallow system is in fact the Condamine Alluvium where there is said to be a problem along the western edge. In the remainder, where 5m is the trigger, the result apply “across the majority of the project development area”. The intermediate system is the Springbok Aquifer, the coal seam system is the Juandah formation of the Walloon Coal measure, and the deep system is the Hutton and Precipice Sandstone aquifers.
Arrow emphasise that these are maximum, worst case drawdowns without mitigation measures. The whole report is here. You really need to look also at Chapter 14, especially tables 14.8 and 14.9. You learn for example that the average drawdown for the Hutton Sandstone is 10 to 20m, and for Precipice it is 1 to 5m. The worst comes in 2035 and 2042 respectively.
But by Table 14.9 after the magic wand of “mitigation, monitoring and management measures” is applied the risk morphs into mostly very low, low and occasionally moderate. These measures are identified. In my untutored view it’s hard to see how they could be all that effective.
There is a lot that you have to take on trust. First, many of the inputs into these models are estimates (educated guesses?). Then you have to believe in the efficacy of the mitigation measures. Many don’t. Finally, we are left with the ‘make good’ provisions.
Just two examples.
Firstly, Arrow advanced the notion of the reinjection of cleaned up water produced in the CSG production process as a mitigating measure. But the process involves collecting water from widely dispersed wells and then cleaning it up and reinjecting it at a central point into a sweet aquifer. There is no other option. Such action will not rebalance the relative pressures where the water was drawn and may create new imbalances where it is injected. We don’t know the long term effects of such measures.
Secondly, if a bore fails then fiddling with it may not be a permanent remedy, especially since the adverse effects are deemed to peak decades into the future. Many would prefer a new bore into a different aquifer. Hillier suggested that the deep Hutton aquifers be accessed. But, he says, that can’t happen under the Water Resource (Great Artesian Basin) Plan, 2006. Lee McNicholl in a letter to the QCL likes the idea and estimates the average cost of a 500m bore at a mere $200,000. This may not be forthcoming, especially towards the end of the CSG production cycle.
Changing the relevant legislation may meet Green resistance, but the ‘make good’ options are limited. They consist of fixing the existing bore, drilling a new one, trucking in water forever (won’t happen) or “other forms of compensation” which presumably means paying for lost production or buying the farm. If the incidence of these situations are going to be as low as suggested, accessing deeper aquifers may not be unreasonable.
Toowoomba Regional Council Mayor Paul Antonio likened the release of the QWC report to the start of a long journey. The appearance of the Condamine bubbles and the reactions of the from the company and the Government suggest that the journey will not always be smooth.
To focus back on the bubbles, I’m inclined to believe Pratsky when he says the locals say it hasn’t happened before. I find it unlikely that a few wells nearby which are not in production and hence not dewatering the coal seam are causing a problem on the scale we’ve witnessed. It seems to me we are left with an adverse effect of CSG activities on the aquifer as a whole or a natural change of considerable proportions, or an interaction of both. We need to know and finding out begins with taking the event very seriously indeed.