This refers to the reports, “Demand to constitute Cauvery Management Board by June 5,” “Voters confront candidates with methane issue” and “Fast against methane extraction” (some Tamil Nadu editions, March 2, 15 & 16), on the hazards of coal bed methane (CBM) extraction in the Cauvery delta. It is heartening that this controversial project will be an important campaign issue in the run-up to the coming general election.
Unconventional commercial production of methane involves drilling, dewatering and fracturing of coal beds. The extraction of CBM, the evil twin of shale gas, is water-intensive. Dewatering coal beds by means of pumping affects groundwater levels and contributory water sources. It causes cavities in coal bed aquifers which then makes shallow aquifers drain into them, triggering water scarcity. Disposal of a large volume of extracted coal bed water requires careful handling. If salty and sodic, it destroys topsoil. Poor growth of cash crops is inevitable. Hydraulic fracking too uses a vast amount of water with fracking liquid, which is a concoction of 600 chemicals. Many of the chemicals in the fracking liquid are known to cause serious health problems including cancer. Other hazards include oil and gas leaks at well as toxic emissions from flares. Minor earthquakes in drilling areas cannot be ruled out.
Once the operation is over, 30 per cent of unrecoverable fracking liquid is left below the ground, enough to contaminate water and threaten agriculture. One doesn’t have to imagine what can happen after drilling 2,000 deep wells coupled with fracking in the fertile Cauvery delta. A complete ban is necessary. As a retired petroleum geologist and as one who is familiar with industry processes, I hope the delta is not reduced to the dismal condition of the Athabasca tar sands of Canada.
K.N. Jayaraman, Thanjavur