This category covers establishments primarily engaged in operating sand and gravel pits and dredges and in washing, screening, or otherwise preparing sand and gravel for construction uses.
212321 (Construction Sand and Gravel Mining)
Construction sand and gravel is a fundamental raw material used primarily by the construction industry. It is among the most accessible of natural resources. Sand and gravel production benefited from growth in the construction industry in the 1990s, but growth diminished into the 2000s as the economy slowed. As a result, construction sand and gravel production in 2002 was approximately 1.13 billion tons, roughly the same as 2001 production. It is estimated that 2003 output will be approximately 1.2 billion tons, up slightly from the previous year. In 2002, about 4,000 companies in 50 states produced 1.3 billion metric tons of construction sand and gravel worth an estimated $5.8 billion. Nine states accounted for about 51 percent of U.S. output of construction sand and gravel. In order of volume, the leading states were California, Texas, Michigan, Arizona, Ohio, Minnesota, Washington, Colorado, and Wisconsin. About 51 percent of the total output was used for unspecified purposes. Of the remainder, 45 percent was used as aggregate in concrete; 22 percent for road stabilization and road base and coverings; 13 percent as aggregate in asphaltic and other bituminous mixtures; 13 percent as construction fill; 2 percent for concrete products, including bricks, blocks, and pipes; 1 percent for plaster and gunite sands; and 4 percent for roofing granules, snow and ice control, railroad ballast, filtration, and related uses.
Sand is composed of particles of feldspar, limestone, slag, gypsum, coral, or quartz formed by such natural processes as erosion and weathering. Gravel consists of pebbles, stones, and rock fragments broken from larger deposits of such minerals as shale, quartz, granite, or sandstone by water or ice erosion. Gravel occurs geologically in riverbeds and seas but is more commonly found in dried-up streambeds formed by glaciers during the Ice Age. Sand is graded for commercial use by passing the grains through standardized sieves, which yield such classifications as very fine, fine, medium, coarse, and very coarse. The five standard gravel sizes are also classified according to the sieves through which they pass. Acceptable sizes for commercial sand and gravel vary with the engineering organization, highway department, or government agency setting the standard and are occasionally revised.
Sand and gravel are primarily used by private construction firms and government agencies in the construction and paving industries. Combined, they take the form of "aggregate" in concrete, portland cement, asphalt, mortar, and plaster, or can be used alone as "fill" in the construction of building foundations, runways, highways, dams, and a wide range of other applications. The commercial use of sand and gravel is so extensive that the growth or decline of production by industry firms is considered a reliable indicator of the country's economic activity.
Roughly 80 to 85 percent of the weight of concrete is typically contained in its sand and gravel aggregate content. In other words, one ton of concrete usually contains about 1,700 pounds of sand and gravel. An estimated 54,000 pounds of sand and gravel are used in the construction of a typical new American home. Traditionally, roughly twice as much gravel is used as sand in the United States. The term fine aggregate is often used to describe commercial sand and coarse aggregate to describe gravel. (In addition to sand and gravel, aggregate might also contain crushed stone.)
In the 1990s firms in the sand and gravel mining industry shared a number of characteristics with other U.S. mining industries, including equivalent production methods for blasting, drilling, loading, transporting, crushing, screening, and "beneficiation" (removal of impurities) of the mineral. Firms in sand and gravel and other mining industries also placed great emphasis on geological, management, and fundamental technical expertise and shared the same environmental, safety, and land rehabilitation concerns.
The sand and gravel mining industry is distinguished from other mining industries, however, by the number and size of its mining operations. Mining firms outside the industry generally operate fewer mines, which are on average much larger than sand and gravel operations. Whereas the market for sand and gravel and other aggregates is highly localized (generally within 40 miles of the quarry), the market for metals and their derivative minerals is much wider (approximately 300 miles for some industrial minerals) and in many cases international in scope. Finally, the amount of capital investment, time, and financial risk required to develop a metal mine is substantially larger than is common in the sand and gravel industry.
In the 1990s the aggregates industry as a whole was a mature industry tied closely to general economic cycles. The range of firms in the sand and gravel industry extended from small, temporary roadside pits working deposits of 20,000 cubic yards with portable equipment to major facilities extracting thousands of tons per day and maintaining stockpiles of processed sand and gravel in excess of 100,000 cubic yards. In the late 1990s the trend in the industry was a continued shift from the small, "family-run" mining operations toward consolidation of industry activities among a few large companies. One factor fueling this trend was the requirement by government environmental agencies that firms entering the industry file environmental impact statements beforehand, which eliminated many prospective small firms with limited start-up capital. Although the majority of industry firms were private establishments, by the mid-1990s more than 50 percent of aggregates consumed went to public construction projects.
Before sand and gravel deposits can be mined, they first have to be located, thoroughly analyzed, and mapped. Geologists, engineers, or other exploratory personnel first consult geologic maps and reports on topography, hydrology, and geology for the potential site, then visually inspect places where the deposits protrude to the surface or are exposed in streambeds and highway "cuts." Samples of the subsurface deposit can be extracted using soil augurs or test borings; electrical resistivity tests or other geophysical tests might also be conducted from the surface to analyze the deposits.
"Petrographic" analyses of deposits supply information about the average shape, hardness, and size of the sand and gravel particles; the amount of sand relative to the amount of gravel; the presence of "coatings" on the rock particles; and the existence of any chemically reactive properties or impurities in the particles. After these analyses are completed, a thorough three-dimensional map of the deposit is prepared indicating the extent, depth, and variation of the deposit.
The optimal sand and gravel deposit contains a wide range of particle sizes, from fine to coarse. It consists of particles that are round, hard, solid, resistant to temperature and moisture changes, chemically inert, and "clean" (free of organic matter, mica, and soil), in sufficient quantities to justify extraction. The ideal deposit is also located near transportation routes to a permanent source of demand for the processed product. Factors such as compressibility, elasticity, thermal conductivity, chemical alkali reactivity, or specific gravity also might be important for sand and gravel intended for special-purpose concretes. In large or laterally extensive deposits, "exploration" by geologists or engineers often continues after mining of the deposit begins. These experts constantly update the levels of overburden (overlaying soil) and grades and supplies of remaining sand and gravel as the deposit is worked.
Because sand and gravel is a readily available commodity of low unit value, the economic viability and final market price of a deposit is determined by such factors as the costs of labor, extraction, and shipment to end-use markets. Transportation costs in the aggregates industry as a whole traditionally average about 50 percent of the price paid by customers, so a deposit located far from transportation or sizable markets might be economically worthless regardless of its extent and quality.
Transportation of the mined sand and gravel to the processing or preparation plant is usually accomplished by conveyor belt, truck, or railcar. The processes employed at the preparation plant to ready the sand and gravel for shipment depend on the nature of the specific deposit and the intended end use. In general, it is washed to remove soil and other impurities, screened or otherwise "classified" to divide it into its various grades, crushed to remove oversized particles, and subjected to various separation techniques to remove remaining impurities and undesirable minerals.
If the sand and gravel mined from a deposit are not of a grade adequate for a market's needs, they can be upgraded artificially at the processing plant by washing, screening, and combining particles until they become the required size. Separation techniques include "sink-float" solutions, in which unwanted impurities sink to the bottom of a receptacle or settling pond while the sand and gravel float, or "heavy-heavy-media" methods, in which gravitational or other forces are used to differentiate the sand and gravel from the impurities. In other methods, separation of sand and gravel from impurities is accomplished using inertial, aerodynamic, or centrifugal principles.
History. Between 1945 and 1966 the sand and gravel industry experienced uninterrupted growth, with combined tonnage of aggregates increasing from 266,000 tons to 1.5 billion tons. Following the completion of the federal government's massive highway construction project begun in the 1950s, industry growth leveled off at roughly 7 percent annually between 1973 and 1988. By 1990, however, the industry was growing by only about 2.5 to 4 percent annually, and it fell off even further during the recessionary years of the early 1990s.
In the mid-1990s the sand and gravel mining industry continued to be affected by fluctuations in demand by the home-building industry, federal construction-oriented legislation such as the Intermodal Surface Transportation and Infrastructure Act, continuing expenses for compliance with environmental regulations (such as the Clean Water Act and Federal Water Pollution Control Act), and cost increases stemming from the longer distances industry firms were forced to cover to bring sand and gravel from their quarries to the end market.
In 1993, however, the sand and gravel industry began to show signs of a recovery from the recession of the early 1990s, its worst period since the Great Depression. Although construction of apartments and office buildings, which traditionally required much larger amounts of sand and gravel than single-family homes, had been stagnant in the early 1990s, construction of highways, power plants, and electrical utility structures rose markedly in 1993. Together with the rise in residential housing starts, this construction spurt contributed to a boom period for the industry that continued through the late 1990s.
In the 1990s trends in the U.S. construction sand and gravel industry centered on three basic factors: consolidation, transportation, and automation and new operating methods. The wave of consolidation that struck the industry in the 1980s continued into the late 1990s as the larger producers gobbled up smaller operations at the rate of about 130 acquisitions a year. As the number of unexhausted quarries near major markets continued to decline, industry firms were also faced with higher costs of hauling their products from increasingly remote quarries. Rail transportation, which had traditionally been reserved for hauls of 300 miles or more, began to edge into the trucking industry's historical hold over the aggregates transport business, and experts predicted that by the year 2046 most sand and gravel would be shipped by railcars.
The industry also began to rely increasingly on automation and innovative methods to streamline the rock extraction and preparation process and cut costs. Underground mining, for example, enabled some industry firms to sidestep the controversial issue of the environmental impact of surface strip mining on unspoiled land. More fuel-efficient equipment, electric rather than gas-powered machinery, and the operation of sand and gravel mines at night promised to reduce the industry's energy costs. Enhanced rock-blasting technology offered improved efficiency and better rock fragmentation, and driverless rock-hauling trucks guided remotely by global positioning satellites promised to reduce employee accidents and personnel costs. Industry leaders increasingly envisioned a future in which highly automated sand and gravel "industrial centers" would incorporate asphalt, ready mix, and pipe production facilities within the traditional quarry. A new emphasis on quality management techniques, customer-driven "value-added" business approaches, and the introduction of new, specifically sized and hybrid aggregate products also hinted at the future shape of the industry.
The passage of the Transportation Equity Act for the 21st Century in 1998 led to an increase in funding for highway construction and maintenance, which in turn assured continued demand for aggregates. In addition, the Balanced Budget Act of 1997 included a provision to increase appropriations to the Highway Trust Fund. This additional yearly amount of $6 to $7 billion was expected to fuel road construction and thereby provide steady demand for construction sand and gravel.
Construction sand and gravel production continued to increase in 1999, and the total outlay for the first nine months of 1999 reached 816 million metric tons, a 2.8 percent increase over the comparable period in 1998. The top five producing states in the third quarter of 1999 were California, Michigan, Ohio, Texas, and Minnesota. Together, the states produced 36.4 percent of the total U.S. output of construction sand and gravel. Among geographic regions, the leading area was East North Central, producing 21.7 percent of the U.S. total. Ranking second among sand and gravel producing regions was the Pacific, which contributed 18.8 percent, followed by the Mountain area, which produced 17.2 percent.
Though the late 1990s were a positive period for the construction sand and gravel segment, construction spending was expected to decline in the early part of the twenty-first century, resulting in lower demand for aggregates, according to the CIT Group, Inc. Public works projects such as road and highway construction were expected to remain steady, whereas residential and non-residential construction were expected to decrease somewhat in 2000. The CIT Group expected that production of sand and gravel would reach record levels in 1999 but fall by 5 million short tons in 2000. Actual output of sand and gravel in 2000 was about 1.12 billion tons worth approximately $5.4 billion.
Construction sand and gravel was a $5.8 billion industry during 2002 with an output of roughly 1.13 billion tons, a total virtually unchanged from 2001. Estimates for 2003 construction sand and gravel production and U.S. consumption were 1.2 billion tons, up only slightly from the previous year. Average unit prices rose about 4.4 percent in 2001 to $5.02 per metric tons over the previous year. Unit prices by usage ranged from a high of $8.86 per ton for roofing granules to a low of $3.30 per ton for fill. The largest increases recorded was for road stabilization, up 33 percent, while the only sector to decline was roofing granules, by 28.3 percent over the previous year. In 2001, some 6,280 construction sand and gravel operations were active in the United States.
Expectations for growth in the industry were meager, due to a sluggish economy and a decrease in spending in road and other construction. The health of construction and related industries are generally indicators of the economy as a whole, and when the economy suffers, so do these areas of commerce. Construction sand and gravel prices were likely to experience a similar trend, estimated to be up only slightly in 2002. With sand and gravel being transported great distances due to local zoning laws, however, delivered prices were expected to rise.
Although mergers, once rampant in the late 1990s, had slowed considerably in 2001, the industry was expected to continue its consolidation in 2002 and beyond. Increasing local resistance to mining—pushing production to rural areas—caused a rise in transportation and other costs. The difficulty for new companies to acquire zoning and permit approvals and install equipment also made acquiring existing, active companies much more desirable. The cost to acquire such companies would likely rise due to these factors.
Recycling had been a trend in the aggregates industry for many years, with a continuously growing number added to the total each year. This type of recycling involved crushing, screening, and reusing cement and asphalt concretes. Aggregates companies were frequently collecting and reusing the materials on construction projects in which they were involved. Some 5.46 million tons of asphalt concrete was recycled in 2001 valued at $25.5 million, a 15 percent increase from the previous year. States leading these recycling efforts, in descending order of tonnage recycled, were Minnesota, California, and Michigan. Company leaders in recycling in order of tonnage produced were Martin Marietta Aggregates, Weber Sand and Gravel, Inc., J.A. Jones, Inc., Midwest Asphalt Corp., and Red Flint Group, LLC.
Safety, health, and environmental restrictions also topped the list of concerns for the construction sand and gravel industry in the early 2000s. The trend toward local zoning and land development regulations discouraging sand and gravel operations was expected to continue to facilitate the movement of sand and gravel operation away from urban and industrialized areas. Thus, shortages were expected to increase in these areas. Environmental issues continued in 2001, as the state Department of Ecology's November rules issued for shoreline protection to prevent further erosion in the state of Washington sparked debate from the industry that argued such laws could completely obliterate the state's sand and gravel industry. The opposition argued that such rules would not ban mining. Other environmental issues in 2002 included whether to renew permits to allow commercial dredging in the Allegheny and Ohio Rivers. Opponents to dredging argued that it affected water supply, caused erosion, and damaged mussel beds, among other things. The majority, however, favored continued dredging, which had been done for a century.
The leading U.S. aggregate-producing firms (including crushed stone) in 2001 were Vulcan Materials Company, with 291 active operations; Martin Marietta Aggregates, with 384 operations; Hanson Building Materials America/Hanson Aggregates, with 181 operations; Oldcastle, Inc./Materials Group, with 173 operations; Lafarge North America, Inc., with 95 operations; and Rinker Materials Corp., with 37 operations. Among construction sand and gravel producers, the leading companies in order of output in 2001 were Hanson Building Materials America/Hanson Aggregates; Oldcastle, Inc./Materials Group; Vulcan Materials Co.; Martin Marietta Aggregates; Aggregate Industries, Inc.; and Kiewit Materials Co.
Consolidation and acquisitions continued to be the trend in the late 1990s. In 1997 Martin Marietta Materials acquired several operations of American Aggregates Corp. from CSR America. This purchase included more than 25 production facilities. The company also bought Nuckolls Aggregates, with operations primarily in north central Iowa. Lafarge's acquisition of Redland Plc transformed Lafarge into one of the largest aggregates producers in the world. It also made Lafarge the fourth largest producer of aggregates in the United States, up considerably from 36th place in 1996. Lafarge's 2001 purchase of the Salt Lake City-based U.S. Aggregates, Inc., made it the largest producer of sand and gravel in Utah. In early 1999 Vulcan acquired Calmat, the leading producer of aggregates in California. Oldcastle Materials bought Hallett Material and Des Moines Asphalt and Paving in 2001, making it the fourth largest producer of sand and gravel in the United States. By 2001, however, mergers had declined by some 23 percent.
Beginning in the late 1970s, foreign acquisitions of U.S. sand and gravel mining firms began an upward spiral that would see thirty major purchases of U.S. aggregate producers concluded between 1979 and 1990 alone. Firms from the United Kingdom, France, Belgium, Ireland, and Australia were among the many foreign owners of U.S. construction sand and gravel producers in the early 1990s. Led by the United States, the North American sand and gravel market was the world's largest in the 1990s, but import-export activity was relatively low. In 1997, for example, U.S. imports and exports accounted for less than 1 percent of domestic consumption. The U.S. exported about 1.43 million tons of construction sand in 1997, primarily to Mexico and Canada. Exports of construction gravel in 1997 dropped 15 percent from 1996 amounts. About 81 percent of total exports of gravel went to Canada. Imports in 1997 reached 1.61 million tons, an increase of about 28 percent from 1996 imports. About 73.9 percent of imported construction sand and gravel was from Canada, and 15.1 percent came from the Bahamas.
In 2001, foreign trade of construction sand and gravel remained slight. Exports grew to 3.05 metric tons, a 27 percent jump from the previous year, but the value dropped to $19.1 million, 21 percent lower than 2000. Imports grew to 3.82 metric tons in 2001, a 33 percent increase with a value of $40.8 million, also an increase from the previous year by 23 percent. Between 1998 and 2001, Canada accounted for 66 percent of American imports, Mexico for 19 percent, and the Bahamas for 4 percent, with the remaining 11 percent from elsewhere.
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Hagey, Jason. "Industry Groups Oppose New Shoreline Rules Hearing: State Board is Reviewing Ecology Department Regulations, Will Issue Findings Later." The News Tribune, 28 June 2001.
Hopey, Don. "River Dredging Facing Few Ripples of Dissent." Pittsburgh Post-Gazette, 5 September 2002.
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