I once watched a documentary called “Gasland” and it was frightening, it was about the extraction of shale gas in US and effects it has caused on the people and the environment. The main concern highlighted in the the documentary was air and water contamination caused by the fracking process, because in the US at the time of filming the companies were exempt from the clean air act and clean water act, while most of the contaminated shown was dirty water some contained chemicals and some could even be set fire to as it came out of tap. While we don’t have shale gas production in Australia we do have CSG which sometimes uses the fracking process, there were also some important points that the documentary failed to mention but I’ll get to that later so lets start with what CSG is and the fracking process.
CSG Well Head
Coal Seam Gas or CSG is methane gas that is extracted from coal seams instead of sandstone where it is normally found, it makes up 27% of Australia’s gas resources, 78% of the eastern states gas resources and is set to supply 50% of the eastern states gas demand by 2030. Coal Seam Gas is pressurised by water which traps the gas in the seam so in order to extract the gas they have to remove the water first, this requires drilling of a well often between 400 and 1000 metres deep and possibly fracking it if gas flow isn’t sufficient.
If drilling and pumping out the water in the coal seam is not enough to get a suitable flow of gas then fracking is required to get enough flow, fracking is a process that involves forcing a mixture of water, sand and a combination chemicals down the hole so that fractures the rock around the well allowing more gas to flow into the gas well. There has been a lot of concern in regards to the chemicals used in the fracking process in particular benzene (which can cause cancer), toulene (a toxic chemical), ethyl-benzene (cancer causing) and xylene (toxic and highly flammable), fortunately these chemicals have been banned in New South Wales and Queensland but there are still many other chemicals used in the fracking process. Although fracking has only been used on eight percent of Queensland’s gas wells the use of these chemicals and the possible contamination they can cause to ground water and waterways is what has got farmers and the producer of the documentary ”Gasland” concerned.
In the documentary “Gasland” they were drilling for shale gas which always requires fracking and may need to be fracked up to eighteen times in its life unlike CSG, so its a bit different but the fracking process is similar as are the depths. As I mentioned earlier the documentary highlighted cases where ground water contaminated by sediments, chemicals and even gas to the extent where it could be ignited as it came out of the tap. But what the documentary failed to mention was that this shouldn’t happen because of the distance between the aquifers that the bore water is found in and the coal seams where the gas is found. Bores for water in CSG areas only tend to around 200 metres but in some parts of Australia they can go down to 2000 metres with the water that comes out being too hot to touch, the coal seam layers are typically found between 400 and 1000 metres, so there’s a large gap between the two meaning the any chemicals that could have entered the coal seam during fracking would take hundreds if not thousands of years to seep through to the aquifers. But in order to get to the coal seam you have to go through the aquifers, so how do they do it without damaging the aquifer?
In order to get to the coal seam you need to drill through the aquifers, so its important to protect the aquifer during the drilling process and during the gas extraction process. To do this they case the gas well with layers of concrete and metal piping as they drill, however it is possible that the concrete could crack and allow gas and chemicals to escape into the aquifer, this is the main theory behind the water contamination and the flammable water seen in “Gasland”. Hopefully a higher level of regulation and tougher casings will prevent these sort of incidents occurring in Australia, although gas wells have been know to leak around the head in Australia. There are also other water issues involving CSG that farmers are more concerned with.
Earlier I mentioned that in order to get the gas from the coal seam it needs be de-pressurised by removing the water from it, this is one of the main concerns for farmers as they need to know what will happen to the ground water level and what will happen to the removed water. The CSG industry expects that will it remove over 75 gigalitres of water a year from the Great Artesian Basin even though the basin has a annual recharge of 880 gigalitres it is spread over a large area and with a large amount of localised pumping it could take many years for the water to come across and refill it. This lack of water flowing back into the pumping area could cause the water in the aquifers above to seep down into the coal seam dropping the water table, this may not happen imminently but over a extended period of time possibly spanning generations and this is what farmers are concerned about. They want to know if the water level will still be there for their children and their children’s children. One of the methods of achieving this is by treating and cleaning the extracted water before it is put back into the ground, this process is called re-injection. Other options for dealing with the extracted water include treating it and using it in cropping operations or town water supply.
The Great Artesian Basin
Company access to farm land is another major concern facing growers, as under Australian Law the land owner owns the land all the way to the core but they don’t own the mineral and fuel resources found in that area. Those resources are owned by the state or the people, the government which is the representation of the people can then issue a mining lease to companies that mine the gas or minerals as long as royalties are paid to the government and the land holder gets compensation. If the landholder refuses the company access and refuses to negotiate with them the matter is taken to the courts and the land holder will be awarded minimal compensation for the mining activity.
CSG is a major issue facing farmers in Australia, it has the potential to do massive amounts of damage to the farming sector but it also has the potential to help out the farming sector. I believe that for the best results farmers need to work with the mining companies and the mining companies need to be proactive in working with the farmers as well as protecting the environment to ensure minimal impact to the land and water. But I also believe that legislation needs to change so land holders can refuse access to their properties.
Please comment and leave your thoughts on the issue.