The classification system by which coal is classified into resource/reserve base/reserve categories on the basis of the geologic assurance of the existence of those categories and on the economic feasibility of their recovery.
Methane (natural gas), while frequently developed with petroleum, also occurs in association with coal and accounts for about 7.5 percent of U.S. natural gas production. Links to digital publications on coalbed methane.
Overview of fractured rock research aimed at understanding the movement of water through fracture networks, and characterize field conditions influencing contaminant migration. Includes programs and publications.