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Both mining and processing of tar sands cause significant environmental impacts, including huge emissions of global warming gases, destruction of wildlife habitat, and impacts to air and water quality. In addition to producing greenhouse gas emitting fossil fuels, tar sands development is significantly more energy intensive than conventional oil and gas development. Greenhouse gas emissions from tar sands production are three times those of conventional oil and gas production, and producing synthetic crude oil emits up to 20% more greenhouse gas emissions than low-sulfur, light crude oils. Tar sands development, which largely has been concentrated in Canada, is becoming the country's largest single emitter of greenhouse gases. In the United States growing interest in tar sands development, especially in the western states, could increase U.S. greenhouse gas emissions from new tar sands projects from 27 to 126 million tons by 2015. In addition, large quantities of water are required for tar sands extraction operations and would draw down surface water flow, adversely impacting stream habitat for fish and other species dependant on local water resources. Drilling one well consumes 5.5 acre-feet of water each year, and the production of one gallon of oil requires thirty-five gallons. Tar sands are composed of clay, sand, water, and bitumen, a heavy black viscous oil, which can be mined and processed. Extracted bitumen is then refined into synthetic oil and other petroleum products. Because the bitumen cannot be pumped from the ground in its natural state, deposits are mined using energy intensive extraction and separation techniques to separate bitumen from the sand, clay and water. Surface tar sand deposits can be recovered by open pit mining techniques, using large hydraulic and electrically powered shovels to dig up tar sands and transport them for extraction using a hot water separation process. Compressed air and steam injection methods are used to extract deep tar sand deposits, and those methods require large quantities of water and energy for heating and pumping. About two tons of tar sands are required to produce one barrel of oil. Tar sands project activities, including grading, excavation and extraction, cause temporary and localized emissions of particulate matter, sulfur dioxide, carbon monoxide and nitrous oxide. In addition, localized emissions of hazardous air pollutants - including benzene, toluene, ethylbenzene, xylene and formaldehyde - pose health risks to nearby residents and project employees. Tar sands processing, upgrading and transport would have long-term regional impacts on air quality from volatile organic carbon emissions, as well as sulfur and carbon dioxide. Up to Top HOME | Email Signup | About Us | Contact Us | Terms of Use | © 2008 Sierra Club |
