Wood Products Use by Coal Mines
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Wood products use by coal mines Robert N. Stone Christopher Risbrudt James Howard Abstract sumption had increased to 53 million cubic feet (Fig. 1). Underground mines (Table 1) accounted for 34 million This study of wood use in mining includes a survey cubic feet and surface mines 19 million cubic feet (Table of 220 coal mining firms to estimate quantities used in 2). 1979. Consumption of wood products by coal mines has The oil crisis of the mid-seventies has changed the gradually declined since 1923. Recent increases in coal demand for timber and timber products. Anticipated production have led to increases in the consumption of substitution of less energy-intensive wood products for wood products by the mine. Wood remains the major plastics, metal, and glass has failed to cause much support material. Mining consumes less than 1 percent greater wood products use. However, rapid changes and of the wood used in the United States. In 1979, mine large increases have occurred in wood fuel usage both timber production was 53 million cubic feet. Infor for home heating and in the forest industries, and more mation on the quantities of wood used for railroad ties, recently, plans for electrical generation. One effect of props, lagging, and many other purposes in the mine is necessary for making estimates of future requirements for wood use in mining. The U.S. Forest Service will use TABLE 1. – Summary of wood products used in underground this information in projecting future requirements and coal mines by region for 1979. removals from U.S. forests, and the Bureau of Mines will use this information for identifying possible supply Region Eastern Midcontinent Western Total problems and research needs. The kind of timber used Use coal coal coal differed by region. Hardwood use is about 40 times greater than softwood use in the eastern region. There, Round props 7,613.7 230.1 564.5 8,408.2 hardwoods are plentiful, relatively cheap, and strong. Sawn props 2,788.6 283.4 – 3,072.0 In the West where softwood forests predominate, soft Split props 781.3 – – 781.3 Lagging 247.1 – 3.0 250.1 woods were 2-1/2 times more common in mine-wood use Crib blocks 3,606.9 86.3 122.3 3,815.5 than hardwoods. Headers 1,434.5 444.0 138.2 2,016.7 Crossbars 12,367.3 1,896.1 85.1 14,438.5 Ties 712.1 136.8 – 848.9 Wedges 3.1 2.5 .7 6.3 Miscellaneous 624.2 26.5 27.2 677.9 Total 30,178.8 3,105.7 941.0 34,225.4 This paper reports on a study to determine the Source: Wood products use in coal mining, Bureau ofMines, U.S. Dept. of the lumber and mine timbers used in mining of coal. Mine Interior, April 1982. timbers are produced from low-quality hardwood trees. The use of timber products in mining has declined in the United States since 1923 when 174 million cubic feet of The authors are, respectively, Supervisory Research Fore wood materials were consumed by the industry. By 1970 ster, USDA Forest Serv., Forest Prod. Lab., P.O. Box 5130, the consumption of mining timbers had declined to 32 Madison, WI 53705; Director, Policy Analysis, Programs and million cubic feet, and to 24 million cubic feet by 1976 Legislation, USDA Forest Serv., Washington, D.C.; and Econ omist, USDA Forest Serv., Forest Prod. Lab., Madison, Wis. (Fig. 1). This trend ended, however, and consumption This paper was received for publication in May 1984. began to rise because of the rising production of coal as Forest Products Research Society 1985. an alternative fuel to oil. By 1979, mine timber con- Forest Prod. J. 35(6):45-52. FOREST PRODUCTS JOURNAL Vol. 35, No. 6 45 Figure 1. – Mine timbers consumed in the United States, selected years, 1906 to 1979. Source: U.S. Dept. of Agri., Forest Serv. An analysis of the timber situation in the United States, 1952-2030. Forest Resour. Rept. No. 23. U.S. Dept. of Agri., Forest Serv., Washington, D.C. 1982. TABLE 2. – Wood use for 1979 in surface mines. timber products to mining firms, and to project future Companies returning survey wood products use in mining. Total Wood Wood use Regional Questionnaires totaling 993 were sent to coal Region NO. production used per ton wood use mining firms requesting information on wood products (MM tons) (M BF) (BF) (M BF) use during 1979 in and outside of their mines. Response Eastern coal 80 30.207 1,764.3 0.0584 10,888.5 Midcontinent coal 23 29.921 2,378.8 .0798 7,083.0 to the mail questionnaire was low, the final return rate Western coal 13 34.650 207.2 .0060 682.3 being 22 percent (220 mines responded). Therefore, a Western lignite 2 11.832 140.4 .0119 831.5 sample of 220 mines provided data by questionnaire in Total 118 106.511 4,490.7 .0424 19,485.3 this comprehensive study of the use of wood products in Source: Wood products use in coal mining, Bureau of Mines, U.S. Dept. of the coal mining. Computer tape listings of 4,529 firms Interior, April 1982. classified as coal mines (Standard Industrial Classi fication Code 1111-Anthracite Coal, and SIC 1211-Bituminous and Lignite Coal) were obtained high oil prices has been the expansion of coal production from Dun and Bradstreet. The sample was selected from (Fig. 2) and the resulting increases in wood products this listing. A number of establishments were rejected production for mining supports and mining activities because they were identified as headquarters for multi (8). Higher production of coal and projections of further location firms. Only single-location firms and branches increases in coal output have led to questions by the of multilocation firms were directly sampled. Of these mining industry about the adequacy of supplies of tra acceptable firms, 432 were identified as strip (surface) ditional wood mining timbers such as props, laggings, mines, and 2,988 others were identified only as coal crib blocks, headers, and other wood products used in mines, neither underground nor strip. underground mining. Firms were selected using a stratified random sam Sampling design pling design. The coal mines were disproportionately sampled according to mine size, as classed by number of The coal industry uses many types of wood products employees. Numbers of mines sampled by employee- in mining operations, especially in underground east size class, in strip and underground mines, are shown in ern mines. The U.S. Department of Agriculture, Forest Table 3. All mines in the two largest mine classes were Service, recently surveyed wood uses by mining firms sampled, and the percentage declined in the smaller for the Department of the Interior, Bureau of Mines (2). employee-size classes to 10 percent in the 0 to 9 class. About 89 percent of the sample consisted of under ground mines, and the remaining 11 percent consisted Mine timber prices of surface mines (2). The survey was part of a study to Prices for mine timbers vary with local and re determine use of lumber and mine timbers in coal gional demands for common timber commodities. There mining for 1979, to estimate the availability and use of is no single market or price structure for mine timbers. 46 JUNE 1985 Most mine timbers are cut or sawn from lower quality or and keep prices from rising greatly in the mine timber small hardwood trees although some softwoods are industry. Another factor in keeping the price for mine used. To get a handle on mine timber prices we evalu timbers stable is newer mining technology. If new tech ated the prices and price trends for several hardwood nology can continue to introduce products such as steel products. An evaluation of prices for commodities such fiber-reinforced concrete cribbing, which is of lower cost as hardwood lumber, hardwood pulpwood, pallets, and than the conventional timber products, mine timber crossties can indicate what might be paid for mining prices could hold or even decline. timber. The trend in prices of mine timbers is expected The hardwood timber resource in the East is more to be similar to that of the above commodities since most than adequate to assure that hardwood and mine timber are hardwood. prices in the region will remain stable for the near Over the last two decades or so there have been future. Except for fuelwood, prices for major hardwood varying trends in the consumption of major hardwood products have shown little change (Fig. 3). For example, timber products. For example, the use of hardwood hardwood stumpage and delivered sawlog prices have pulpwood showed a significant increase, and the con shown very little increase since 1952 when compared to sumption of fuelwood has increased sharply. softwood stumpage and delivered sawlog prices. However, it appears that supplies of timber will be Pulpwood stumpage prices have shown declines. adequate to meet demand for most hardwood products Wisconsin aspen prices for delivered pulpwood declined between 1960 and 1980, while aspen real stumpage prices have remained almost constant throughout the period. The real stumpage prices of four primary pulp wood species, namely jack pine, black spruce, aspen, and balsam fir, showed mixed results after adjusting for inflation (4). Real delivered price increases for pulp wood have shown no percentage change over the period from 1961 to 1979. Figure 3. – Trends in price and price indexes for Figure 2. – Coal production trends in the United States. hardwood products. TABLE 3.