The objective of this study was to assemble the largest possible body of information concerning the regulatory and classification process applying to the incidence of methane gas in metal and nonmetal mines in a number of foreign countries. An extensive literature search was performed to identify countries with appropriate experience. Of the 20 countries that were approached, 16 responded with information of varying degrees of detail. Eight of the 16 countries--Australia, the Republic of South Africa, the Federal Republic of Germany, Yugoslavia, France, Spain, Italy, and the United Kingdom--were visited to obtain firsthand information from industry representatives and the regulatory agencies. The results of the 8-month study are presented.