Mineral Commodities
For convenience of discussion, the mineral commodities are separated into four groups: Fuels, construction materials, nonmetals and metals. The principal or only use of most commodities is indicated by group name; a few, however, are more widely used in Appalachia for other purposes than indicated by the conventional grouping. For example, peat is used as a packing material and soil conditioner rather than as a fuel; asphalt is a construction material. Most lime is used for chemical, metallurgical, and agricultural purposes; comparatively little is used in construction. Bauxite mined in Appalachia is for use as a chemical or refractory material rather than a source of aluminum.
(Please note that the sections on the following subjects are not reproduced here, although some of the figures are: Fuels (Asphalt, Heavy Crude Oil, and Shallow Oil Reservoirs, Coal, Oil Shale, Petroleum and Natural Gas), Construction Materials (Cement, Clay, Miscellaneous Clay and Shale, Fire Clay, Kaolin, Pottery and Stoneware Clay, and Potassium-Bentonite.)
By. Robert G. Stansfield, George E. Fish, Jr.,
and Stanley A. Feitler, U.S. Bureau of Mines
Crushed stone is the term applied to rock that has been crushed or ground to standard sizes after quarrying. Included in this classification are large, irregular stone blocks, known as riprap, used chiefly for protection against the wave and current action of water. For statistical purposes, commercial crushed stone produced in Appalachia is classified into the following groups: Limestone, granite, marble, sandstone, and miscellaneous stone.
The largest use of crushed stone is for concrete aggregate and roadstone. In 1964, 63 percent of the national production was used for this purpose. Crushed limestone for cement manufacture ranked second composing 14 percent of total output. Considerable quantities of stone are also used for riprap, railroad ballast, roofing granules, and filtration beds. Additional uses of limestone, the most important of the crushed stones, are: fluxstone, agricultural limestone (agstone), lime manufacture, asphalt and fertilizer fillers, alkali manufacture, glass manufacture, stone sand, whiting, sugar refining, and refractory (dolomite) uses. Table 60 shows quantity and value (1958 constant dollars) of crushed stone sold or used by producers in Appalachia, in 1963 and 1964.
Table 60. Crushed and broken stone sole or used by producers in the Appalachian Region, by uses.
In areas where they are readily available, sand and gravel and blast furnace slag can be substituted for crushed stone for most construction purposes. Since the end of World War II, blast furnace slag has largely replaced limestone in the manufacture of mineral wool. Slag is also substituted for limestone in the manufacture of cement. Lightweight aggregate can be used instead of stone in some concrete, where the higher costs can be justified.
The growth of the crushed stone industry in the United States resulted chiefly from the increased use of concrete in construction and from the expansion of road and highway systems. From the turn of the century until World War I, production increased slowly. Highway and building construction grew rapidly in the prosperous era before 1929. Demand declined in the depression years but was sustained to some extent by Federal projects (Bowles and Jensen, 1943, p. 6, 7). Just before and during the early years of World War II, the demand for cement and for other crushed stone products increased greatly for the construction of airfields, manufacturing plants, military establishments, and shipyards. In the past two decades, accelerated highway and general construction activity resulted in remarkable additional growth in the crushed stone industry.
Annual domestic production of crushed stone increased 360 percent from 1945 to 1964 and Appalachian output expanded 280 percent. For the 20-year period, Appalachia produced 1,059 million tons (table 61), or about 13 percent of the U.S. production. In 1964, Alabama, Pennsylvania, and Tennessee contributed slightly more than one-half the total Appalachian output and Georgia, Virginia, and West Virginia produced about one-fourth of the output.
Table 61. Production of crushed stone, 1945-64.
(Includes: granite; basalt (traprock); limestone and dolomite; marble; sandstone; quartz, and quartzite; slate; calcareous marl; and miscellaneous stone. United States totals excludes the limestone used for cement and lime for 1945-53; excludes shell.) (Source: U.S. Bur. Mines)
Limestone (here used to include dolomite) is by far the most important type of crushed stone. It was one of the earliest materials utilized by the pioneer settlers, being used for building stone and burned for lime more than 200 years ago. In the last two decades, 86 percent of total Appalachian crushed stone output was limestone. Table 62 shows the annual production of crushed limestone in Appalachia and the United States for the period 1945-64, the record year, Appalachia produced 15 percent of the national total.
Limestone was produced in all Appalachia States in 1964. The three major States producing about 60 percent of the output were Tennessee, 17.2 million tons; Alabama, 14.3 million tons; and Pennsylvania, 13.5 million tons. Combined production of Virginia, West Virginia, Kentucky, and Ohio constituted 33 percent of total output.
In 1964, 63 percent of Appalachian limestone production was used for concrete aggregate and roadstone. Use for manufacture of cement, about 15 percent, ranked second. Most of the remainder went into fluxstone, agriculture limestone, railroad ballast, riprap, refractory stone, and for lime manufacture.
Table 62. Production of limestone and dolomite (crushed and broken stone), 1945-53 (Source: U.S. Bur. Mines)
Granite ranked second in Appalachian crushed stone production, the 73.2 million tons produced during the 1945-64 period (table 63), was 7 percent in total crushed stone output. The annual rate of production has steadily increased to a maximum of 9.6 million tons in 1964 which was 17 percent of the total U.S. output (table 63). Georgia, North Carolina, and South Carolina, listed in order of output, accounted for the bulk of Appalachian production.
Table 63. Production of granite (crushed and broken stone), 1945-64 (Source: U.S. Bur. Mines)
More than 95 percent of 1964 production was used for concrete aggregate and roadstone. Other uses included riprap, railroad ballast, stone sand, and poultry grit.
Sandstone, a category that includes quartz and quartzite, constituted 5 percent of Appalachian crushed stone production during the last two decades. Annual quantities and values of production in Appalachia and the United States for that period are presented in table 64. Record Appalachian production was in 1963, partly because of increased demand for sandstone in the construction of a rock-fill dam in West Virginia. In 1964, Appalachia produced 15 percent of the total domestic output of crushed sandstone.
Table 64. Production of sandstone, quartz, and quartzite (crushed and broken stone), 1945-54. (Source: U.S. Bur. Mines)
The three principal sandstone-producing States, accounting for about 81 percent of Appalachian output in 1964, were: Pennsylvania, 2.7 million tons; West Virginia, 0.5 million tons; and Tennessee, 0.2 million tons. The remaining 19 percent of output originated in the Appalachian part of Ohio, Virginia, North Carolina, Alabama, and Georgia.
In 1964, 83 percent of production was used for concrete aggregate; most of the remainder was used for refractories (ganister). Smaller quantities were used for riprap, cement, glass manufacture, railroad ballast, foundry sand, and abrasives.
Marble made up 1.5 percent of Appalachian crushed stone production during the 1945-64 period. Annual production and values in Appalachia and the United States for that period are presented in table 65. Maximum production was in 1964, when output in Appalachia was 77 percent of the national total and was 20 times the Appalachian production of 1945.
Table 65. Production of marble (crushed and broken stone), 1945-64. (Source: U.S. Bur. Mines)
Marble production was reported in 4 of the 12 Appalachian States in 1964. In order of output, these are: Georgia, Alabama, North Carolina, and Tennessee. In 1964, about 30 percent of production was sold or used as roadstone, the largest use. Other uses included terrazzo, paint and putty, neutralizer, and roofing gravel or chips.
Small amounts of slate, basalt, calcareous marl and other rocks are used in Appalachia for crushed stone. Slate was less than 1 percent of Appalachian crushed stone production during the 1945-64 period; annual production and value in Appalachia and the United States for that period are presented in table 66. The principal use was for lightweight aggregate. From 1945-54, basalt (traprock) was less than 1 percent of Appalachia crushed-stone production and was used for concrete aggregate. The combined calcareous marl and other stone output also accounted for less than 1 percent of the total Appalachian crushed stone production during the same period.
Table 66. Production of slate (crushed and broken stone), 1945-64. (Source: U.S. Bur. Mines)
Rocks suitable for crushed stone are abundant and widespread in Appalachia and constitute a vital resource for present and future industrialization and urbanization. The crushed stone industry of Appalachia has grown steadily during the past two decades and, with the economic development expected during the next decade or two, should grow even more rapidly. Future use patterns will probably remain about the same, most crushed stone being utilized by the building industry and in highway construction.
By William L. Newan, U.S. Geological Survey,
and Robert G. Stansfield and Nils A. Eilersten,
U.S. Bureau of Mines
The early settlers in Appalachia used slabs of surface stone, field stone, and boulders for building foundations, basement walls, dams for mill ponds, bridge abutments and piers, and similar types of basic construction. As the demand for building material increased with the expansion of population and industrial centers, reliable sources of useful stone were sought. Numerous deposits were found within short haulage distances, and quarrying became an important industry. Some quarries produced stone of such excellent quality that they attained early fame throughout the construction industry and attracted widespread markets. These sources have continued to supply stone for many of the Nation's important buildings and monuments.
Dimension stone includes blocks and slabs of natural stone that satisfy requirements for use as building stone, monumental stone, paving blocks, curbing, and flagging (Currier, 960, p. 7). Structural uses of stone include foundations, walls, chimneys, sills, steps, and trim in buildings, and in engineering structures such as retaining walls, sea walls, and bridges. Bowles (1917, p. 23-25) lists four principal forms of building stone: cut or finished stone, ashlar, rough building stone, and rubble. Cut or finished stone has been shaped and sized accurately and may even be carved or surface tooled or polished; ashlar is stone that has been squared into rectangular blocks with rock-faced (broken), sawed, or planed surfaces. Rough building stone consists of rock-faced blocks of various shapes and sizes. Rubble, the cheapest form of building stone, consists of irregular blocks having one good face. Monumental stone may be considered as the finest quality of cut or finished dimension stone. Uniformity of texture, attractive coloration, freedom from flaws, and suitability for carving and polishing are the principal requisites. Paving blocks are small brick-shaped blocks used for roads, docks, freight yards and other surfaces subjected to heavy abrasive traffic. Curbing consists of long slabs of stone used for edging roadways and sidewalks. Flagging consists of thin slabs used for walks, driveways, and paved areas such as patios, carports, and courtyards.
According to their particular uses, dimension stones are chosen for such qualities as strength, hardness, durability or resistance to weathering, and ornamental features, and these qualities depend, in turn, upon mineralogic composition, texture, structure, and color. Consumers have developed a variety of specifications for dimension stone, which are described in reports of the American Society for testing and materials. In addition to these qualities, other factors are considered in selecting sites for quarry operations. The stone must be sound and not fractured and shattered nor extensively cut by mud seams or shale splits. There must be a sufficiently large volume of sound stone which is easy to quarry and transport to mills and markets.
In Appalachia where supplies of dimension stone of nearly every type are virtually inexhaustible, economic factors limit production. The volume of production depends largely upon the rate of industrial activity, particularly in the building trades, and cost is always an overriding consideration. A rise in dimension stone production characterizes the prosperous years; depressed economic conditions lead to stagnation of the industry. The demand for stone is generally created by architects and designers and by the vagaries of the consuming public, and style trends dictate, to a marked degree, the kinds of dimension stone that are quarried and how they are to be used in construction. Formerly, walls were constructed chiefly of massive blocks of stone carefully shaped and fitted to bear the entire weight and stresses of the structure; but a growing practice is to use natural stone as veneer or thin panels, fixed and keyed upon a basic framework of steel and concrete. A current trend in stone veneer is the use of precast panels of concrete faced with exposed quartz-pebble aggregate.
Dimension stone is commonly shipped long distances to satisfy special architectural demands, and the cost of transportation is an important factor in competitive marketing. The amount of handwork required in quarrying and shaping building stone also places it at a disadvantage when compared to the production methods in the manufacture of concrete block, brick, and cast "stone."
In former years dimension-stone quarries often were opened just to supply stone for a local project. Architects today, however, prefer to utilize stone of proven suitability because tests to forecast the durability of untried stone are not generally accepted. The American Society for Testing and Materials is developing specifications and test methods for a variety of dimension stones, which in time may alter the situation.
At the beginning of this century, dimension stone was produced in much greater tonnage than crushed stone. However, by 1964, dimension stone was only one-half of 1 percent of the total tonnage of domestic stone production, largely because of the growth of the crushed stone industry to supply stone for concrete highways and buildings. Even in 1925, the year of greatest U.S. production of dimension stone (4.8 million tons), the building stone output, which was the major segment of dimension stone production lagged behind the pace set by construction because of the increasing use of concrete and steel in commercial buildings. The record low production year of this century was 1942. Since World War II, domestic production of dimension stone has shown a gradual increase. Table 67 shows annual production with quantities and values, of dimension stone produced in Appalachia and the United States for the period 1945-64.
During the 20 years covered in table 67, dimension stone produced in Appalachia accounted for 22 percent of the value and 14 percent of the tonnage of U.S. production. All Appalachian States reported output, but Virginia production was from outside the Appalachian area. Tennessee, Ohio, and Georgia, listed in order of output, accounted for 65 percent of Appalachian production, while Pennsylvania, New York, North Carolina, and Alabama contributed 34 percent.
Table 67. Production of dimension stone,
1945-64.
(Includes granite, marble, limestone, sandstone, and miscellaneous
stone.
Excludes basalt and slate. Source: U.S. Bur. Mines)
Marble is limestone or dolomite that has been metamorphosed or recrystallized into a rock composed mainly or wholly o crystals of the minerals calcite or dolomite or mixtures of both. Some unmetamorphosed limestone is sufficiently pure and crystalline to take a high polish and in the trade is called "marble." This type of limestone is included with true marble for purposes of this report. Impurities, chiefly iron oxides, produce various colored patterns which lend life or tone to the marble. The valuable varieties of marble are distinguished chiefly on the basis of color. Statuary marble is the purest and whitest, architectural marble has the most uniform tones of color, and ornamental marble is distinguished by striking effects of varied colors.
Deposits of the various kinds of marble occur throughout long narrow belts within the Valley and Ridge, Blue Ridge, and Piedmont provinces in the southeastern part of Appalachia (fig. 60). Descriptions of the important belts follow.
Nearly all limestone used as dimension stone in Appalachia is obtained from small quarries developed to supply local building needs. Because they lack the special decorative or ornamental qualities that marble generally possesses, the limestone products are seldom transported great distances nor are unusual demands created for them by vogue or style trends. Nevertheless, suitable limestone is widespread throughout Appalachia and it has, in the past, provided vast amounts of building stone.
Figure 60. Distribution of marble, granite, and slate in the southern part of the Appalachian Region.
(This map includes the following: Marble belt: Luttrell, Black Oak, Galbraith, Concord, Knoxville, French Broad, and Bays Mountain; Igneous and metamorphic terrane includes belts of granite and gneiss that are or may become major sources of dimension stone; Production center for dimension granite locations; zone of metamorphosed rocks containing slate-bearing areas; Area containing known deposits of dimension slate; and Production center for dimension slate.)
Tennessee marble, a very pure nonmetamorphic limestone of the Holston Formation of Middle Ordovician age, is quarried from beds in the Valley and Ridge province in eastern Tennessee that crop out in a series of roughly parallel belts that trend north-eastward over an area 12-16 miles wide and about 125 miles long (fig. 60).
The repetition of the marble beds is caused by complex folding and faulting and subsequent exposure through erosion. The width of each belt generally does not exceed one-fourth mile, but in places a belt may attain widths of a mile or more. The thickness of the Holston Formation may be as much as 400 feet, but, owing to variation in texture and structural defects, its workable beds are generally not more than 60-80 feet thick. According to C. H. Gordon (1924, p. 28), the marble ranges in color from light pink and gray to deeper shades of red and chocolate, is coarse textured, and is relatively impervious to stains and soiling. There is no practical limit to the amount of marble available in the beds, but supplies of certain colors or grades of marble may be limited.
Gordon (1924, p. 30) identified several major belts of marble, shown in figure 60: the Luttrell belt, the Galbraith belt, the Black Oak belt, which is interrupted by faulting and erosion, the Concord belt, the Knoxville belt, the French Broad belt, and the Bays Mountain belt. The beds of marble are not commercial grade throughout the various belts. Gordon (192, p. 31) stated that the best and most productive deposits are found near the middle of the area.
The Meadow belt, not shown because of scale limitations, parallels the Knoxville belt at a distance of about half a mile. Lenses of marble also occur irregularly within the overlying Tellico and Ottosee Formations, and the marble of the Meadow belt may represent such lenses. Attempts to work them have generally proved unsuccessful because of their small size and inferior quality of stone.
According to Maher and Walters (1960, p. 1), the first development of Tennessee marble was the opening of a quarry in Hawkins County, Tenn., in 1838 (fig. 60, loc. 1). Subsequently, marble from this area (loc. 2) was used in the construction of the National Capitol in Washington, D.C. In 1862, a quarry was opened in the Knoxville, Tenn., area (loc. 3) where the marble is generally flat lying and outcrops are extensive. The quality of the marble plus favorable quarrying conditions helped establish Knoxville as the center of the marble industry in Tennessee. (Other important quarries are located at Friendsville (loc. 4), Louisville (loc. 5), Concord (loc. 6), and Luttrell (loc. 7). The principal fabricating mills are at and near Knoxville (Gildersleeve, 1946f, p. 6).
Extending northeastward in the Valley and Ridge Province into Virginia is the apparent continuation of the Luttrell belt of Tennessee. Boyd (1881, p. 207) reported Chickamauga Limestone in Scott County (fig. 60, loc. 8, 9) as containing large masses of gray and purple marble or coarse-grained limestone with flesh-colored spots. According to B. N. Cooper (1945, p. 133-134), this stone becomes progressively more argillaceous to the northeast, and in the vicinity of Hansonville, Russell County (loc. 10), is not suitable for use as building stone. Another belt of Chickamauga Limestone near Sharon Spring (loc. 11) in Bland County, contains a coarse-grained gray marble that was described by Watson (1907, p. 77) as being a desirable building stone. Commercial deposits undoubtedly are present throughout this belt, but to date only small amounts of stone have been quarried to supply local needs.
Marble of commercial grade is widely distributed throughout Giles County, Va., but is produced only for local needs and chiefly from the area near the junction of Walker Creek and New River.
All rocks in the area have been subjected to intense deformation, and limestone of at least four formations has been, in places, metamorphosed into marble. The formations are: (1) Copper Ridge and Nittany Dolomites of Cambrian and Ordovican (sic) age, (2) the Murfreesboro Limestone of Ordovician age, (3) the Moccasin Limestone of Ordovician age, and (4) the Romney Shale of Devonian age (Mathews, 1934, p. 7). The Moccasin Limestone is the most important and, according to Mathews (1934, p. 11), consists of an upper red member and a lower marble member that ranges in thickness from 60 to 121 feet. The uppermost part of the lower member is thin bedded and dark reddish brown. The lower beds are much thicker, more compact, and variable in color, ranging from a variegated carnelian and light Nile-green to gray with golden bands. Commercial-grade marble is distributed throughout the base of the member, and Mathews (1934, p. 31-32) listed many localities favorable for prospecting.
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