AN INTRODUCTION TO ISSUES IN ENVIRONMENTAL GEOLOGY OF OIL SHALE AND TAR SANDS

The critical environmental issues for the development of oil shale and tar sand are novel versions and combinations of familiar problems. They involve the consumption of water at the front end, the potential contamination of water and the atmosphere at the back end, and challenges to habitat and range in the middle. Interactions of ground water, surface water, soil, rock and air create a linked system that is an exciting challenge to the research community, but one which will also challenge that community to communicate effectively the results and implications of their research. The extraction of useable hydrocarbons from the very heavy oil of the tar sands and the solid kerogen of oil shale requires a larger input of energy than traditional hydrocarbons, raising questions of energy return on investment and carbon footprint. Water use is also potentially higher for these resources, despite advances in conservation and reuse of process water. The mobilization of hydrocarbons underground, the target of several production schemes for both oil shale and tar sand, carries the potential for contamination of ground water. The potential for surface mining and processing to contaminate surface and groundwater through particulate air emission is a potentially novel contaminant pathway not yet clearly addressed. The large areal extent of both types of resources raises significant issues about how to manage land to preserve ecosystems in the regions where these resources exist. This introduction to the theme session will identify individual issues addressed in the session, draw on related information from the 30^th Oil Shale Symposium, and other recent conferences, and will attempt to give an image at least of the interacting systems potentially impacting the environment in the locations where oil shale, tar sand, and oil sand exist.