tages not only caused by embargoes, but since fossilfuels are a non-renewable resource, from just depleting the worlds finite supply. As seen in the seventies when the price of oil rose drastically, interest in coal mining was renewed and such will be the case again. Coal is the most abundant fossil fuel on the face of the earth (see Fig. 6) and its use was only discontinued because the other, less abundant, fuels were cheaper to transport. As our reserves of natural gas and oil deplete the law of supply and demand states their price will go up until such a time where coal once again becomes competitive in the industrial market.As well there are various technologies that exist in order to change the form of coal so it is more easily transported. Currently there are two processes; Gasification and Liquefaction. Coal gasification is a process for converting coal partially or completely to combustible gases. After purification, these gases - carbon monoxide, carbon dioxide, Fig. 6 Energy content of the world's initial supply of recoverable fossil fuels is given in units of 1015 thermal kilowatt-hours. Coal and lignite, for example, contain 55.9 x 1015 kilowatt hours of energy and represent 88.8 percent of the recoverable energy. Source: Siever, 1978.hydrogen, methane, and nitrogen - can be used as fuels or as raw materials for chemical or fertilizer manufacture. There are many techniques to accomplish this but all involve heating the coal with steam in the absence of air. Currently the heat from burning this gas amounts to only 15 to 30 per cent of what can be obtained with an equal volume of natural gas (Montgomery, 1990). Coal liquefaction is a process that involves first the manufacture of carbon dioxide and hydrogen gases from the coal. Heating these gases in the presence of a certain catalyst at high temperatures will cause them to be transformed into liquid hydrocarbons (petroleum). Currently these processes are unecon...
