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Wood products use by 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 use in mining includes a survey cubic feet and surface mines 19 million cubic feet (Table of 220 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 -intensive wood products for wood products by the mine. Wood remains the major , , 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 . 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 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 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. , 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 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 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 . 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 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 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 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 , 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 . There mining for 1979, to estimate the availability and use of is no single market or price structure for mine timbers.

46 JUNE 1985 mine timbers are 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 . If new tech­ ated the prices and price trends for several hardwood nology can continue to introduce products such as ­ 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 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 ­ 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. – Size classes of coal mines and sampling scheme. Strip mines Underground mines All coal mines Employee No. No. No. class size Total sampled Percent Total sampled Percent Total sampled Percent 0-9 221 22 10 1,411 141 10 1,632 163 10 10-99 199 80 40 1,248 499 40 1,447 579 40 100-999 9 9 100 225 225 100 234 234 100 1,000 + 0 – – 17 17 100 17 17 100 Total 429 111 26 2,901 882 30 3,330 993 29.8 Note: Ninety mines had no employment figures and were not included. Source: Wood products use in coal mining, Bureau of Mines, U.S. Dept. of the Interior, April 1982.

FOREST PRODUCTS JOURNAL Vol. 35, No. 6 47 Real delivered price increase rates (6) products. The most often mentioned is steel-fiber­ reinforced concrete mine support members (SFC). Test Products 1947-1961 1961-1979 results indicate that it appears technically and eco­ (%) (%) nomically feasible to use SFC cribbing as a substitute Pulpwood 0.8 0 for wood cribbing for mine roof supports. Sawlogs (hardwood) 0 1.5 Veneer logs Total wood use (hardwood) 1.9 2.5 Large quantities of wood products are used in coal mining operations within mines, primarily in roof sup­ Stable hardwood prices, by most measures, indicate ports. Other uses are for walls, floors, and rail ties. the hardwood resource is large and increasing. Between Outside the mines, lumber and plywood are used for 1952 and 1977 the inventory of hardwood timber rose 43 shacks, and utility poles are used. With coal expected to percent, increasing from 178 billion cubic feet to 255 play an increasingly important role in the foreseeable billion. During the period from 1952 to 1977 the East future, wood for mining use will prove to be a valuable showed some expansion in hardwood sawtimber inven­ resource. U.S. coal reserves are estimated at 438 billion tories. As , most of the hardwood inventories are in short tons (7). Of this reserve, 297 billion tons are eastern forests, much of it near the major coal mining suitable for underground mining methods and capable areas. of recovery by current . Total 1979 produc­ tion amounted to 781,498 thousand tons, of which ap­ Much of the hardwood sawtimber inventory is con­ proximately 41 percent was from underground mines. centrated in the lower diameter classes; nearly two- thirds of the total is between 11 and 17 inches in dia­ Wood use per ton of underground coal mined was meter at breast height. This timber is suitable for the found to vary substantially by mining process and re­ manufacture of pallet lumber and ties. All of the hard­ gion. Figure 4 shows the three coal mining regions in wood timber is suitable for use as pulpwood, fuelwood, the United States. In the eastern coal region, 1.6 board and mine timber. feet of wood was used per ton of coal, well above the 0.6 Given the adequacy of hardwood in the East, most board foot usage per ton in the West. Wood use per ton of regions can expect prices for mining timbers and similar coal mined underground is shown in Table 4. The kind of hardwood commodities to remain stable. The greatest timber used also varied by region. impact on mine timber prices will result from the im­ Wood products used by mines largely come from pact of technology and the introduction of cost-saving nearby forests and wood processors. Consequently, the

Figure 4.– Coal mining regions in the United States.

48 JUNE 1985 TABLE 4. – Wood use per ton of underground coal mined by process. As the proportion of coal mined by strip methods in Room-and- Combined a region increases, the wood use per ton declines. In the Region pillar methodsa Total eastern region, about 56 percent of coal production comes from underground mines, and the wood use per Eastern coal 1.486 1.774 1.608 ton is highest of the four regions. In the midcontinent Midcontinent coal .340 (b) .340 Western coal .387 1.353 .559 and western coal regions, 37 and 16 percent, respec­ tively, of production comes from underground mines. aLongwall and room-and-pillar. bNo respondents. Note: No underground mining apparently occurs in the Western Lignite Surface uses Region. Source: Wood products use in coal mining, Bureau of Mines, U.S. Dept. of the In surface mines, wood use per ton is comparatively Interior, April 1982. low, since none is necessary for roof support. In all regions, wood use is less than one-tenth of a board foot per ton of surface coal production. Typical uses are small TABLE 5. – Wood use per ton of underground coal mined, temporary , props and blocking for machinery, by hardwood and softwood. and miscellaneous applications. Surface coal mines in Region Hardwood Softwood the eastern region account for slightly over half of the wood used nationally in this type of mining. The mid- Eastern coal 1.567 0.040 continent region accounts for about 36 percent of the Midcontinent coal .340 (a) total use. Total use in surface coal mines is about 19.5 Western coal .158 .401 million board feet (Table 2). aNo data. Note: No underground mining apparently occurs in the Western Lignite Wood-use categories Region. Source: Wood products use in coal mining, Bureau of Mines, U.S. Dept. of the Round props. – Round props are used to support Interior, April 1982. mine roofs. A prop is loaded perpendicularly to the roof and floor for maximum strength. Props are used in faces, mine entries, and along haulage corridors. They kinds of wood used vary with forest character. For are required to have a diameter of not less than 1 inch example, hardwood use is about 40 times greater than for every 15 inches of length, but in no case should they softwood in the eastern region. In the eastern wood­ be less than 4 inches in diameter. , hardwoods are plentiful, relatively cheap, dense, Nearly 55 percent (57 mines) of the underground and strong. In the West where softwood forests pre­ mines returning questionnaires reported purchasing dominate, 2-1/2 times more softwoods were used than round props in 1979. About 91 percent of the props in hardwoods. Hardwood and softwood used in under­ underground coal mines in the United States are used in ground mines in each region is reported in Table 5. the East. Nearly 98 percent of eastern props are hard­ In the eastern region, initial installations in mine wood, with locust, hickory, oak, and elm being used. entries and faces each use about one-third of the wood Black locust, offering excellent structural properties used in the mine. Subsequent rehabilitation in mine and a high decay resistance, is a preferred species. entries is the next most significant use, at 14 percent. Locust is also a prized wood for fenceposts, among other Wood use in other areas of mines, e.g., shafts, slopes, uses. In the midcontinent region, approximately 83 and other, is minimal for both initial installation and percent of props are hardwood, primarily oak. Softwoods subsequent rehabilitation. accounted for nearly 56 percent of prop material in the West, with lodgepole pine and spruce the preferred Initial installation in mine entries is the major use species. Oak is the only hardwood species mentioned as of wood products in the midcontinent region, requiring prop material in the West. 57 percent of the wood employed. The only other sig­ Round props accounted for nearly 25 percent of nificant area of wood use is in the initial installation total wood volume reported in the survey (Table 1). of faces. Sawn props. – Sawn props serve the same purpose Wood use in the western coal region is very similar as round props. They are preferred by some mines for to the eastern region, averaging about one-third each their ease of handling. Sawn props are often set in for initial installation in mine entries and faces. Sub­ mining corridors which tend to be permanent (3 to 10 sequent rehabilitation is also substantial in mine en­ tries, but not in any other use. yr.). Approximately 8 percent of the underground mines reported purchasing sawn props in 1979. Of the total Underground uses wood volume, 94 percent was treated. The standard Total wood used nationally for underground mines measures for eastern mines are 1.72 cubic feet per piece is about 34.2 million cubic feet. A summary of wood with a mean length of 6.5 feet. For midcontinent mines, products used in underground coal mines is shown in sawn props contain 2.09 cubic feet of wood and are 9 feet Table 1. The greatest single wood use, both nationally long. No sawn props were reported purchased by west­ and in any region, is crossbars. Crossbars are the most ern mines. Hardwoods accounted for all of the sawn prop used product in both the eastern and midcontinent material with oak, hickory, and black locust the pre­ regions. In the western region, round props are the most ferred species. Wood purchased for sawn props accounts used product. Much of the wood used in underground for nearly 9 percent of all wood reported in the survey coal mining occurs in the eastern region (88%). (Table 1).

FOREST PRODUCTS JOURNAL Vol. 35, No. 6 49 Split props. – Split props normally conform to the underground mines that responded to the survey re­ same standards as round props. Split props are halved or ported purchasing headers in 1979. Approximately 19 quartered depending on the original diameter. As such, percent of all wood purchased for header use was soft­ they have the versatility to be used for other purposes wood. Softwoods comprised 13 percent of eastern, 24 such as wheel chocking or lagging. Nearly 13 percent of percent of midcontinent, and 55 percent of western underground mines returning the questionnaire re­ header material. Headers accounted for approximately ported purchasing split props in 1979; all were in the 5.9 percent of all wood purchased in the survey. eastern region. Ninety-nine percent of the split props Header use rates did not decrease with size of mine. reported were untreated hardwoods, usually oak, pop­ The greatest use for headers occurred when coal produc­ lar, beech, or locust, totaling 781,300 cubic feet. The tion was between 100,000 and 500,000 tons, resulting in remaining volume was 11,000 cubic feet of untreated a use factor of 0.1207. The header use per ton declined to softwood. Split props accounted for slightly more than 2 0.0729 when coal production exceeded 500,000 tons. percent of the total wood volume reported in the survey. The quantity of headers used in underground coal Amounts of wood used as split props per ton of coal mines was 24,291 thousand board feet in 1979. Of this mined decline as the mines become larger. total 19,761 thousand board feet was hardwood and Lagging. – Lagging received very little use in 4,530 thousand board feet was softwood. mining operations in 1979. Lagging is generally de­ Crossbars. – Crossbars are typically used in con­ scribed as having planklike dimensions (thick boards to junction with props and headers. They help support the 10 ft. long) used as shoring sides of mine entries, shafts, mine roof by spanning two parallel mining props. and haulage ways. It can be stacked lengthwise and Crossbars are generally 10 to 16 feet long, and as such crosswise on top of crossbars for roof support. Since it is are suitable for use as rail ties or sills (footers.) This often utilized as roof beams, some lagging may have high use could explain in part the comparatively large been reported as crossbars. Approximately 7 percent of quantities of wood classified as crossbars. Approxi­ the underground mines reporting purchased lagging for mately 32 percent of the underground mines answering use in 1979, of which 92 percent is hardwood. All wood the survey reported purchasing crossbars in 1979. Soft­ purchased for lagging in the western region was soft­ wood crossbars accounted for approximately 77 percent wood. Even so, softwoods accounted for only 8 percent of of crossbar use in the West and about 9 percent of total lagging wood. Wood purchased for lagging accounted for crossbar use for all regions. Wood purchased for cross­ less than 1 percent of the total purchased wood in the bars accounted for about 42 percent of total wood re­ survey. Lagging per ton of coal mined also decreased ported purchased in the survey. steadily with larger mine size. The quantity of lagging The quantity of crossbars used in underground coal used in underground coal mines was 3,012 thousand mines was 172,870 thousand board feet in 1979. Of this board feet in 1979. This total is composed of 2,774.8 total, hardwood was 157,241 thousand board feet, and thousand board feet of hardwood and 238.1 thousand softwood was 15,629 thousand board feet. Crossbar use board feet of softwood. per ton of coal increased by mine size although, for Crib blocks. – Crib blocks are used as support pil­ mines exceeding 1/2 million tons of production, crossbar lars behind the working face of a coal seam. Cribbing use declined slightly. material is required, by and Health Admin­ istration (MSHA) Standards (5), to be of wood having Ties. – Ties, apart from their use as railway sup­ flat, parallel sides, and in no case should the crib be less ports, are quite frequently rehabilitated for other uses. than 30 inches square. Hardwoods are preferred as They are used to provide a large bearing surface against cribbing material in the eastern and midcontinent coal a soft or muddy floor, or sawn and stacked like crib mining regions, and account for 95 percent of total crib blocks for pillar support. Twenty-three percent of the use. The majority of crib blocks was used in the eastern coal mines returning the questionnaire reported pur­ region. Softwoods accounted for 96 percent of total crib chasing ties in 1979. Hardwoods, mostly oaks, were the blocks used in the West. Wood purchased for crib block strongly preferred tie material, accounting for greater usage amounted to just over 11 percent of the total wood than 99 percent of all wood used for ties. Wood used for purchased in the survey. Use of crib blocks per ton of ties accounted for 2.5 percent of the total purchased coal mined also declines significantly as mine size wood in the survey. increases. The quantity of ties used in underground coal The quantity of crib blocks used in underground mines was 849,000 cubic feet in 1979. Of this total coal mines was 45,964 thousand board feet in 1979. This 843,000 cubic feet was hardwood and 6,000 cubic feet total is composed of 43,784 thousand board feet of hard­ was softwood. wood and 2,180 thousand board feet of softwood. Wedges. – Wedges are pie-shaped slabs of wood Headers. – Headers, also referred to as caps, provide typically 7 by 7 by 1 inch and tapered to 0 inch. They are a bearing surface against mine roofs. They are con­ normally sawn at the mill and ordered in thousand- ventionally mounted on top of props to fill gaps and piece lots. They are “wedged” on top of headers to tighten the wood structure to the mine roof. Headers are tighten props to the mine roof. Coal mines keep a large one mine support product where metal has sub­ supply of wedges on hand since they can be used for any stantially replaced wood. Metal headers account for purpose requiring tightening or blocking of a support about 30 percent of header use and are preferred for structure. Twenty-five percent of the mines answering long-term use (5 to 10 yr.). Forty-eight percent of the the survey reported purchasing wedges for use in 1979.

50 JUNE 1985 The average purchase was 150,000 pieces. Wedges used utility markets. The need for wood will depend pri­ in the West are generally larger than those used in marily on how effectively wood can compete with other other areas of the United States, with 10 by 10 by 1.5 products (3). Projections of future wood use in coal inches being the standard size. Because of their small mining were made as part of the study based on primary size, no species was preferred, and it is assumed that any energy figures obtained from an Energy Information wood, be it hardwood or softwood, suffices as wedging Administration report on energy forecasts. The fore­ material. With a mean volume measure of approxi­ casts reflect three distinct world oil price scenarios– mately 0.125 board foot per piece, wedges accounted for low, midrange, and high. In the low-range scenario, coal approximately 0.5 percent of total wood reported in the will not substitute for oil as much as in the high-range survey. Although large numbers of wedges were re­ scenario, and hence more coal will be required for the ported used in the survey, the total wood volume is high oil price-range scenario. Coal will be relatively small because of their generally small size. Further, much cheaper than oil, and more coal than oil will be wedges are often made at the mines from scrap mate­ consumed. rial, e.g. the short pieces remaining after props have To calculate figures for future wood usage in coal been cut to length. mining, regional wood-use figures for 1979 were linked Miscellaneous uses. – Miscellaneous uses of wood in to projected underground coal production. Underground coal mines include brattice lumber for ventilation struc­ coal production in the East was 55 percent of the re­ tures, floor planking, rib boards, and lumber and ply­ gion's total coal production in 1979. This percentage is wood for general in-the-mine . Twenty per­ projected to rise to 93 percent in 1995 and hold at this cent of the mines responding to the survey reported level through 2030. For the western region, under­ purchasing wood for miscellaneous purposes in 1979. ground coal production amounted to 16 percent of west­ Miscellaneous wood products account for 2 percent ern coal production in 1979. The share of underground (160,103 ft.3) of all wood volume reported in the survey; coal production is expected to decline to 11 percent of the of this, 40 percent was softwood. total by 1995. This is due to the expected expansion of Wood use outside the mine. – Mines utilize wood surface production in the region. No changes in wood products in temporary shacks, permanent buildings, products use per ton of coal mined are incorporated in utility poles, survey stakes, rail ties, and many other the projections. Wood-use factors are held constant uses outside of the mine itself. Because of the great throughout the 30-year projection period (3). variety of uses, few of which employ wood products in Projections for the low, midrange, and high price large quantity, data collection for these proved difficult. range for oil show wood products use in underground To have calculated specific product use per ton of coal coal mining could increase 3.3 times between 1985 and mined would have resulted in extremely small ratios 2015 (Table 6). In the low range about two-thirds of the since few wood products were used in quantity. use of wood will remain in the eastern coal region and In the eastern region miscellaneous lumber use about three-tenths in the midcontinent coal region. In averaged about 760 board feet per mine per year. For total, wood products use in underground coal mining the midcontinent and western coal regions, use per under a midrange oil price scenario is expected to in­ mine averaged 280 and 30 board feet, respectively. crease 3.9 times. By 2030, projected wood use will reach 181 million cubic feet. Outlook for the mine-timber market In the high oil price scenario, coal consumption is Future wood requirements of the mining industry projected to be higher than the low or midrange sce­ will depend on the demand for coal and the need for narios because the difference between coal and oil prices wood in coal mining. The demand for coal is keyed to the is greatest; of course, wood use is also larger than in the demand of the industrial, export, coking, and electric other scenarios. Nationally, wood use in this scenario

TABLE 6. – Projections of total coal production and wood products consumption in underground coal mines for a low, midrange, and high oil price scenario.a Scenario Year Low Midrange High Wood Wood Wood Underground products Underground products Underground products production use production use production use (MM tons) (M ft.3) (MMtons) (M ft.3) (MMtons) (M ft.3) 1985 508.8 44,988.9 502.3 44,358.9 497.2 44,109.3 1990 751.0 67,148.6 750.8 62,215.4 742.8 66,590.7 1995 928.5 83,893.2 935.8 84,545.9 922.9 83,515.0 2000 1,015.6 89,988.3 1,034.7 91,589.5 1,025.2 90,829.1 2005 1,052.4 92,109.3 1,084.5 94,755.6 1,082.5 94,592.4 2010 1,143.4 99,500.8 1,215.2 105,200.3 1,235.1 106,785.6 2015 1,270.9 110,160.4 1,421.2 122,173.0 1,481.3 127,098.2 2020 1,441.9 125,1317 1,642.8 142,824.5 1,708.8 148,489.7 2025 1,572.7 138,167.1 1,857.0 161,927.9 1,939.5 168,334.6 2030 1,686.3 148,285.1 1,979.1 172,293.0 2,083.2 180,804.0

aCoal production figures adapted from: Wood products use in coal mining, Bureau of Mines, U.S. Dept. of the Interior, April 1982.

FOREST PRODUCTS JOURNAL Vol. 35, No. 6 51 will increase about four times, from 44 million to 181 market for low-quality hardwoods found in abundance million cubic feet by 2030. The expected expansion of throughout the East. Many are engaged, at surface coal production in the West will make increases least part time, in supplying the needs of the mining in coal consumption and wood use figures inconsistent industry. All the mining operations tend to use the local until about 2015. During this time underground mining species of wood, hardwood or softwood. will once again be on the rise. Conclusions Literature cited Wood products used in producing coal from under­ 1. ANDERSON, G.L., and T.W. SMELSER. 1980. Development testing ground mines play an important role in the industry. and analysis of steel-fiber-reinforced concrete mine support mem­ Coal cannot be mined from underground without sup­ bers. Bureau of Mines Rept. of Investigation, U.S. Dept. of the porting the roof and often the sides of the mining shafts. Interior. 2. BUREAU OF MINES, U.S. DEPARTMENT OF THE INTERIOR. 1982. Wood For this use, wood is a valuable resource. As the Nation products use in coal mining. April. requires more domestic coal, wood products will also be 3. KNUTSON, R. 1970. A look at the mine-timber market in the needed in greater quantities. Appalachian Region. USDA Forest Sew. Res. Pap. NE-147. 9 pp. On a national scale, however, wood products used 4. LOTHNER, C.D., E. KALLIO, and T.D. DAVIS. 1950-1980, Minnesota in coal mining are a small portion of total wood con­ and Wisconsin Forest Product Prices: A Historical Review. U.S. sumption; use in underground coal mines amounts to Dept. of Agri., Forest Sew., North Central Forest Expt. Sta., Duluth, Minn., April 1982. about 0.24 percent of the national consumption of indus­ 5. MINE SAFETY AND HEALTH ADMINISTRATION. 1979. Title 30. Feder­ trial roundwood of 14.0 billion cubic feet (excluding al Code of Regulations. Section 75.200-8 through 75.200-14. fuelwood) in 1979. Even in the future, as wood use in 6. SKOG, K., and C. RISBRUDT. 1982. Trends in economic scarcity of U.S. timber commodities. USDA Forest Sew. Resource Bull. FPL mining grows as projected, the timber resource is ade­ 11. Forest Prod. Lab., Madison, Wis. April. quate to provide the additional hardwood timber. 7. U.S. DEPARTMENT OF ENERGY. 1979. DOE Energy Information In local , the amount of wood products Administration annual report to Congress, Washington, D.C. 8. . 1982. Quarterly coal report. Energy Information Ad­ required by coal can be important, and can cause ministration Office of Coal, Nuclear, Electric, and Alternate Fuels, shortages and price changes. Mining props provide a Washington, D.C. 20585. January-March.

52 JUNE 1985