Construction Sand and Gravel
Figure 1. Dredging gravel from the Mississippi River near Hannibal, Marion County, Mo. Right: Photo shows the gravel barge being unloaded.
Construction sand and gravel are different size detrital particles or fragments used for building, paving and various other developments. Detrital material consists of particles and fragments detached from pre-existing rocks either by erosion or weathering. Various scales have been developed for describing the different sizes of these particles and fragments (Figure 2). Sand and gravel sizes are utilized in construction while clay and silt (fines) are too small for most construction uses.
Engineers consider sand to be rock or mineral grains with diameters between 0.074 mm (retained on U.S. standard sieve No. 200), and 4.76 mm (passing through U.S. standard sieve No. 4) (Figure 2, ASTM). Geologists consider sand to be a detrital rock fragment or mineral particle smaller then a granule and larger than a coarse silt grain, having a diameter in the range of one-sixteenth to 2 mm (62-2,000 micrometers or 0.0025-0.08 inches, or 4 to -1 phi units, or a size between that of the lower limit of visibility of an individual particle with the unaided eye and that of the head of a small wooden match). Usually, the term sand also is applied to describe a loose aggregate of unlithified mineral and rock particles of sand size; an unconsolidated or moderately consolidated sedimentary deposit consisting of essentially medium-grain detrital particles. The material is most commonly composed of quartz resulting from rock disintegration, and when the term “sand” is used without qualification, a siliceous composition is implied; but the particles may consist of any mineral composition or mixture of rock or mineral fragments, such as “coral sand” consisting of limestone fragments.
Figure 2. Various particle size classifications commonly used by engineers and industry.
Gravel is an engineering term for rounded fragments having a diameter in the range of 4.76 mm (retained on U.S. standard sieve No.4) to 76 mm (3 inches). Geologists define gravel as an unconsolidated, natural accumulation of typically rounded rock fragments resulting from erosion, consisting predominantly of particles larger than sand (diameter greater than 2 mm, or one-twelfth inch), such as boulders, cobbles, pebbles, granules, or any combination of these fragments; the unconsolidated equivalent of conglomerate rock. It is usually a term used for a loose accumulation of rock fragments, such as detrital sediment associated especially with streams or beaches, composed predominantly of more or less rounded pebbles and small stones, and mixed with sand that may compose 50-80 percent of the total mass.
Construction sand and gravel production is an indicator or the overall health of the construction industry and thus an indicator of the state’s overall economy. During the construction boom of the mid 2000s, Missouri produced nearly 17 million short tons of construction sand and gravel during the year 2006, a record. In 2010, Missouri produced nearly 12 million short tons of construction sand and gravel valued at more than $73,000,000.
Composition of Sand and Gravel
Although the gravels and sand of Missouri can vary significantly in their lithological or mineralogical compositions, some generalizations are applicable on a basinal or regional scale.
- Missouri River – Higher in lignite than the Mississippi River above its confluence with the Missouri River. Sand fraction primarily composed of quartz. Gravel is predominantly chert.
- Mississippi River – Sand fraction primarily composed of quartz. Gravel is predominantly chert. Igneous and metamorphic gravels more common in the Mississippi than the Missouri River. Floodplain gravels are rounded to subangular above the confluence with the Missouri River.
- Ozarks – Chert gravels are the dominant commodity from Ozark streams and rivers. Some quartz sand can be found in streams where Ordovician sandstones (e.g., St. Peter Sandstone) are exposed. In the St. Francois Mountains, large percentages of granite, felsite and mafic gravel are present.
- Glacial Till Plains of northern Missouri – North of the Missouri River, glacial drift up to 400 feet is present. Sand size ranges from fine to coarse with the majority being medium to coarse. The sand is predominantly quartz. The lithology of the gravels varies significantly. The gravels consist of chert, limestone, quartzite, granite and mafic rocks. The majority of the sand and gravels are in a clay matrix that is easily removed by washing.
- Southeast Missouri Lowlands – The “Lafayette” gravels that mantle Crowley’s Ridge are the primary source of gravel in this region. Sand is produced from the Tertiary age Holly Springs Formation. These deposits consist of interbedded gravel, sand and clay deposits. The gravel is typically a brown chert. The sand is principally quartz being dominantly medium to coarse size.
Economic deposits of construction sand and gravel primarily occur in the channels and flood plains of rivers and streams. Major producing basins in Missouri include the Missouri, Mississippi and Meramec rivers. Currently, 58 of 114 Missouri's counties are active producers of construction sand and gravel (Figure 3).
Figure 3. Current construction sand and gravel production in Missouri.
Construction sand and gravel have many uses, past and present. The most common uses are listed below.
- Sand for Mortar
- Stone Masonry
- Sand and Gravel for Concrete Aggregate
- Roofing Gravel
- Sand for the manufacture of Sand-Lime Brick
- Paving Sand
- Sand and Gravel for Pavement Foundations (Road Base)
- Sand for the Cushion Layer
- Sand for Asphalt Pavements
- Gravel for Roads
- Road Aggregate/Metal
- Rural Roads
- Gravel for Railroad Ballast
Construction sand and gravel have been used on a local basis since before Missouri became a U.S. state. Historically, the cumulative total product of the greater St. Louis area (St. Louis County and City, Jefferson, Franklin and St. Charles counties) accounts for nearly 70 percent of the state’s total sand and gravel production (including industrial sand). In this region, gravel is principally mined from the Meramec basin. Sand is produced commonly from the Missouri and Mississippi rivers. This area still accounts for the majority of sand and gravel produced in the state. Principal producers in the greater St. Louis area include Fred Weber Inc., Lafarge NA, Simpson Sand & Gravel Inc., St. Charles Sand Company and Winter Bros. Material Company. Other principal producers in the state include Holliday Sand & Gravel and Mid America Sand LLC.
Figure 4. Historical construction sand and gravel production in Missouri.
Figure 5. Historical value of construction sand and gravel produced in Missouri. Values have not been adjusted to account for inflation.
Figure 6. Historical price per short ton of construction sand and gravel produced in Missouri. Values have not been adjusted to account for inflation.
Common Terms Used in the Construction Sand and Gravel Industry
Fill (engineering) – (a) Man-made deposits of natural earth materials (e.g., rock, soil, gravel) and waste materials (e.g., tailings or spoil from dredging), used to fill an enclosed space such as an old stope or chamber in a mine, to extend shore land into a lake or bay, or in building dams. (b) Soil or loose rock used to raise the surface of low-lying land, such as an embankment to fill a hollow or ravine in railroad construction. Also, the place filled by such an embankment. (c) The depth to which material is to be placed to bring the surface to a predetermined grade.
Fill (geological) – Any sediment deposited by any agent to fill or partially fill a valley, sink, or other depression.
Building Sand – Sand used in erecting buildings, particularly used for making mortar and wall plaster.
Paving Sand – A type of commercial sand that is divided into three general usage classes; concrete pavements, asphaltic pavements, and grouting sand. Sand for concrete pavements according to the U.S. Bureau of Public Roads, should all pass a one-quarter inch screen, 5 to 25 percent should be retained on a No. 10 sieve, from 50 to 90 percent should be retained on a No. 50 sieve, and not more than 10 percent should pass through a No. 100 sieve. Not more than 3 percent of the weight should be matter removable by elutriation. For asphaltic pavement, small amounts of organic matter are not objectionable in the sand. All should pass a one-quarter inch screen, 95-100 percent through a No. 10 sieve, 80 percent through a No. 20 sieve, and 5 percent through a No. 200 sieve.
Concrete Aggregate – Normal concrete aggregate includes sand, gravel, crushed rock of various types and slag. The nomenclature is given in British Standards, 812. The mineralogical composition is dealt with in American Society for Testing and Materials, C294 and C295.
Road Metal – Also called road aggregate, this rock is suitable for surfacing roads and for foundations, asphalt and concrete roadways; also used without asphaltic binder as the traffic-bearing surface, generally on secondary roads.
Roofing Granule – A particle of rock or fired clay approximately No. 9 mesh, used to manufacture roofing shingles.
Roofing Gravel – Gravel placed over asphaltic roofing material, especially buildings with flat roofs. The gravel helps keep tar and other asphaltic roofing materials from melting and cracking and thus leaking.
Gunite Sand – A mixture of sand and cement, sprayed with a pressure gun onto roofs and ribs to act as a sealing agent to prevent erosion by air and moisture.
Reference and Further Reading
Dake, C.L., 1918, The sand and gravel resources of Missouri, Missouri Bureau of Geology and Mines, vol 15, 2nd series, 274p.
Neuendorf, K.K., Mehl Jr., James P., and Jackson, J.A. (Editors), 2011 Glossary of geology. American Geosciences Institute, Alexandria, VA, 783p.
Thrush, Paul W. (editor), 1968, A dictionary of mining, mineral, and related terms, U.S. Dept. of the Interior, Bureau of Mines, Washington D.C., 1269p.
Sand and gravel mining in Missouri is regulated by the the department's Land Reclamation Program.