This industry consists of establishments primarily engaged in mining or quarrying crushed and broken limestone, including related rocks, such as dolomite, cement rock, marl, travertine and calcareous tufa. Also included are establishments primarily engaged in the grinding or pulverizing of limestone, but establishments primarily engaged in producing lime are classified in SIC 3274: Lime.
212312 (Crushed and Broken Limestone Mining and Quarrying)
Crushed limestone production is the largest of three related industries that extract and process nonfuel, non-metallic minerals. Primarily employed as aggregate, which refers to a wide number of sand, gravel, and stone mixtures, crushed stone is an essential component of the U.S. infrastructure because of its use in the construction of highways, airports, river locks and dams, railroad ballast, and breakwaters. It is, however, considered a "high-volume, low-value commodity" with relatively stable prices since the 1970s, according to the U.S. Geological Survey.
The crushed stone industry is the largest nonfuel mining industry in the United States, with 3,300 quarries in 49 states as of 2003. Limestone and related rocks account for the vast majority—71 percent in 2003—of crushed stone production and sales in the United States. The essential make-up of limestone is calcium carbonate (CaCo3). If 10 percent or more of magnesium carbonate is present it is called "magnesian" or "dolomitic" limestone. Usually the term "limestone" acknowledges the presence of dolomite.
After growing by an average of 3 percent in the late 1990s, crushed stone production began to decline in the early 2000s, falling by 2 percent to 1.49 billion tons in 2003. However, a 3.2 percent increase in production was
expected for 2004. Total crushed stone output in 2003 was valued at $8.6 billion.
In the past most crushed and broken stone has been mined from open quarries. Today, the trend has been more toward underground mining. Underground room-and-pillar mines are operated on a year round basis and do not require as much material removal. Additionally, underground mining requires less surface space and consequently avoids the ever-increasing cost of land. Another benefit for the underground mine operator is the availability of valuable storage space.
The high cost of transporting crushed stone has dictated that stone be mined and quarried as near as possible to the market centers or manufacturing plants that use it. However, increasing land values and environ-mental concerns have made it necessary to move crushed stone quarries further away from customers and have driven up the cost of the delivered material for some producers. Overall, however, prices have remained stable since the 1970s, growing just over the rate of inflation due in part to productivity gains and competition.
The average unit value of crushed stone is also expected to increase as a result of rising costs of labor, energy, and the rising costs of processing equipment. In the area of environmental concern, most states are now requiring crushed stone operations to submit environ-mental impact reports, and soon a reclamation plan and a use permit application will be required.
In the early 2000s, ten states accounted for more than half of the total U.S. output of crushed limestone and dolomite: Texas, Florida, Pennsylvania, Missouri, Illinois, Georgia, Ohio, North Carolina, Virginia, and California. The central and eastern regions of the United States contain its largest reserves of limestone. Two of the leading U.S. producers in 2003 were Martin Marietta Materials Inc., which had strengthened its limestone operations by purchasing Redland Stone Products Company in 1999 and the limestone assets of Brauntex Materials Inc. in 2001 and Florida Crushed Stone Company, which was acquired by CSR America in 2000 and later sold to Pinker Materials Corp.
Among market economy countries, the United States is far and away the largest producer of crushed and broken stone. Major international producers include Australia, Canada, Germany, France, Japan, and the United Kingdom. Because of high transportation costs, the international crushed stone trade remains quite minor. Nearly 86 percent of the tiny U.S. crushed stone import market is held by Canada and Mexico.
The outlook for limestone, and crushed stone in general, was generally favorable in the early 2000s. The U.S. Geological Survey predicted in 2004 that increased spending on infrastructure, largely the result of a recovering U.S. economy and legislation such as the Safe, Accountable, Flexible, and Efficient Transportation Equity Act of 2003, would boost demand for crushed stone and other construction aggregates.
"Cat D400E Series II Ejector Trucks: Helping Florida Crushed Stone Out of a Sticky Situation." Construction Equipment, March 2002.
"Martin Marietta Announces Acquisitions" Ceramic Industry, May 2001.
U.S. Geological Survey. Mineral Commodity Summaries, January 2004. Available from http://minerals.usgs.gov/minerals/pubs/mcs/2004/mcs2004.pdf .