Coal Seam Gas Application
A Petroleum Production Lease(PPL)must be applied for, compared to Natural Gas, which exists in a high pressure environment, CSM is under low pressure; this means that the mining company has to plan for a high density of wellheads in any area so that the CSM mine to be economically viable.
Health and Safety
CSM extraction. has many health hazards. The water taken from the coal seam is toxic. After the water has been removed from the coal seam, the dynamics of the coal seam have been changed causing the methane to be freed up and migrate; hopefully to the well head, however rocks can and do have fault lines by which the methane can find alternate avenues to the surface. There are many instances of methane coming out of household taps. CSM wells and pipelines are fire hazards; over 50% of wells tested in Queensland leak methane. They do sometimes catch fire and explode. Once the methane has been freed up from the coal, nothing will stop it flowing.
Water tables
CSM mining poses a serious risk to fresh water aquifers. The huge volumes extracted from the coal seam can then lead to a major depletion of connected aquifers which would be used for drinking water, agriculture and fire fighting. The assortment of chemicals used for drilling and fraccing cause serious contamination to fresh water aquifers and running groundwater streams and rivers.
Environment
The pollution of water tables and rivers leads to the mass death of all types of living creatures and plants. The installation of full scale industrial machinery scares away wildlife. The uncontrolled venting of fugitive methane emissions poisons the atmosphere.
The Law
Environmental regulation is minimal and government generally relies on information supplied by the industry. There is no independent review of the potential impacts of developing a CSM mine on community, health and environment. Local council has no power in the process. Exploration Licences cover most of NSW,.
Reproduced and adapted with the permission of Lock the Gate Alliance Inc. www.lockthegate.org.au The official version - Australian Mine Atlas. Methane Gas (CH4) is recognised as a valuable resource. It is usually mixed with carbon dioxide, other hydrocarbons and nitrogen.
Formation
CBM forms by either biological or thermal processes. During the earliest stage of coalification (the process that turns plants into coal) biogenic methane is generated as a by-product of microbial action (similar to the mechanism which generates methane in council landfills). Biogenic methane is generally found in near-surface low rank coals such as lignite. Thermogenic methane is generally found in deeper higher-rank coals. When temperatures exceed about 50°C due to burial, thermogenic processes begin to generate additional methane, carbon dioxide, nitrogen and water. The maximum generation of methane in bituminous coals occurs at around 150°C. The methane produced is adsorbed onto micropore surfaces and stored in cleats, fractures and other openings in the coals. It can occur also in groundwaters within the coal beds. CBM is held in place by water pressure and does not require a sealed trap as do conventional gas accumulations. The coal acts as a source and reservoir for the methane gas while the water is the seal.
Extraction Technology
CBM is produced by drilling a well into a coal seam, hydraulic fracturing the coal seam then releasing the gas by reducing the water pressure by pumping away the water. Hydraulic fracturing of the coal seam is done by pumping large volumes of water and sand at high pressure down the well into the coal seam which causes it to fracture for distances of up to 400m from the well. The sand carried in the water is deposited in the fractures to prevent them closing when pumping pressure ceases. The gas then moves through the sand-filled The Den. Issue 19, March 2011  13.