It is estimated that coalbeds in the United States contain as much as 11.3 trillion m3 (400 trillion ft3) of in-place gas (Kuuskraa and Brandenburg, 1989). This volume of gas represents a source of clean-burning fuel; however, methane emissions into underground coal mines present a serious hazard to coal miners. Since the first documented major U.S. coal mine explosion in Virginia in 1839, several thousand fatalities have been recorded as a result of explosions where methane was a contributing factor (Skow et al., 1980). Ventilation has been the primary means of controlling methane in coal mines for many years. However, as mines began operating in deeper and gassier coalbeds, supplemental means of methane control became of interest to mine operators. The shift to mining gassier coalbeds is quite evident in Figure 1, which charts the methane emissions from coal mine ventilation systems from 1971 to 1988. The volume of methane and the number of operating mines remained stable through the early to middle 1970s (Irani et al., 1972, 1974), but as of the 1980 and 1985 surveys (Grau and LaScola, 1984; Grau, 1987), methane emissions increased substantially, while the number of operating mines declined. The decline of methane emissions in 1988 is at least partially attributed to the increased use of methane drainage technology, especially in the Black Warrior basin of Alabama. Methane emissions from Alabama coal mines decreased 17%, from 2.3 x 106 m3/d (82.4 MMcfd) to 1.9 x 106 m3/d (68.4 MMcfd) between 1985 and 1988 (Trevits et al., 1991) Coal, “the black rock that burns,” is the subject of song, story, and legend. The earliest literature citation of coal (combustible bodies, some of which by inference must be coal) is credited to Aristotle in his treatise “Meteorology,” which may date near the middle of the fourth century B.C. Theophrastus, a student of Aristotle, at what is probably a slightly later date provides descriptions of different forms of coal based on their behavior in combustion, identifies areas of occurrence, and states that it was used by smiths (footnote by Hoover to Agricola, 1556). Though the Greek philosophers are responsible for the earliest known literature citations, China and perhaps other parts of eastern Asia are usually believed to have preceded the Mediterranean area in recognition of coal as a peculiar material with usable properties. Inouye (1913) states that although there is no authentic record of the history of the Fu-shun coal field in southern Manchuria, “it is said that the coal was used as fuel … for copper smelting in times as remote as 2,000 or even 3,000 years ago.” Fires through most of man’s history have been fed by “traditional fuels"—wood, straw, dung, and other plant materials. That coal could be of complementary usage is recorded in the remains of funeral pyres in Wales, dated about 3,000 years ago (Lindbergh and Proverse, 1977). However, the versatility of coal was not widely appreciated, and the discovery and use of charcoal satisfied most needs of primitive metal-working. By the end of the