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<br />. <br /> <br />l\:) <br />t- <br />en <br />10- <br /> <br />. <br /> <br />. <br /> <br />APPENDIX B: COAL RESOURCES <br /> <br />The western states are endowed with a wealth of energy resources <br />ranging from fossil fuels to nuclear materials. Of these, coal is in <br />greatest abundance, has contributed extensively to the economic growth <br />of the United States, and is expected to increase its contribution in <br />the future. The Upper Colorado River Region has an estimated 139 <br />billion tons in the reserve of coal underlying the surface at various <br />depths. The total coal resource has not yet been quantified and new <br />discoveries every year add to the great potential of this Region. These <br />resources are distributed throughout the three aggregated subareas <br />(ASAs 1401, 1402, 1403) with about 55 percent located in ASA 1401. <br />Of these estimated resources, it is generally assumed that approxi- <br />ma~ely one-half of the coal in-place is recoverable, based on existing <br />technology. This is known as the "recoverable reserve". <br /> <br />Several characteristics of western coals make them particularly <br />advantageous for use u~der modern energy requirements and current air <br />pollution restrictions. Among these are the low sulfur and somewhat <br />variable ash content, medium to high Btu values, and generally good <br />quality bituminous and subbituminous coal ranks. The relatively low <br />sulfur and ash qualities are parciculariy good because of increasing <br />concern about air pollution in major urban areas. <br /> <br />Coal is classified and discussed according to its characteristics. <br />Of these, rank is most useful as a descripco~. Rank is based on per- <br />centa1e of fixed carbon and heat content in Btu, with ranges from 7,000 <br />to over 15,000 Btu/lb being considered economical to extract (Kevsto~e, <br />1977). Coals having 69 percent or more fixed carbon on a dry, mineral- <br />matter-free basis is classified according to fixed carbon, regardless of <br />calorific value (Averitt, 1975), while those with less fixed carbon are <br />classified primarily by Btu. Coal is classified in ranks rangin~ from <br />anthracite (86-98 percent fixed carbon) at the top through semi-bituminous, <br />(14,000-15,000 Btu/lb), bituminous (10,500-14,000 Btu/lb), subbitumir.ous <br />8,300-10,500 Btullb) Ancl lignite (6,300-7,000 Btu/lb) (Averitt, 1975). <br />Subbituminous is further subdivided into ".\," liB, II and lIe" in order of <br />decreasing overall quality. Coal rank varies widely from deposit to <br />deposit, making it a highly variable parameter. Generally speaking, <br />older coals--those deposited first--are of higher rank, but coals which <br />have been subjected to the heat and pressure of metamorphism tend to <br />increase in rank. <br /> <br />The process of coal deposition and formation is a slow one, <br />involving continued deposition of layers and gradual compaction of <br />organic. material over centuries. The general rule governing this forma- <br />tion is the thicker the strata and deeper the deposition, the higher <br />the quality (rank) of the coal. It is estimated that a I-foot thick <br />bed of bituminous coal contains several centuries of accumulated plant <br />material (Averitt, 1975). Several geologic factors are considered to <br /> <br />B-1 <br />