The reason that oil shale and tar sands are of particular interest to the Utah Chapter of the Sierra Club is that compared to “conventional” crude oil sources they require more water to produce and release more greenhouse gases when extracted and refined. Surface mining of OS/TS also has the potential for significant land disturbance and poses threats to wildlife. Of all the fossil fuels (i.e., carbon-based fuels extracted from geologic formations, including coal), oil shale and tar sands are sometimes referred to as “the dirtiest fuels”. Further, OS/TS production has the potential to lead the country further into fossil fuel dependence and away from cleaner, renewable energy.
Oil shale and tar sands are natural geologic sources of a waxy petroleum substance that can be converted into fuel. Oil shale is a consolidated sedimentary rock bearing kerogen, which when heated, releases crude oil or natural gas. Tar sands are unconsolidated sediments bearing the same or similar substances. Both kinds of geologic deposits occur in the upper, northern reaches of the Colorado River Basin: areas of eastern Utah, western Colorado, and southern Wyoming. The extensive Green River geologic formation is particularly rich in oil shale, and occurs in eastern Utah’s Uinta Basin. The Uinta Basin contains one of the richest oil shale deposits in the world.