Sand, gravel, and crushed stone operations
Sand, gravel, and crushed stone are commonly produced in Kansas for a variety of uses, especially in building and road construction. Referred to collectively as aggregate when used as construction material, sand, gravel, and crushed stone can be mixed with other materials to make concrete, mortar, asphalt, and other products or used unblended as railroad ballast, construction fill, and road cover. Thousands of unpaved roads across Kansas are made from sand and gravel or crushed rock.
Most of the sand and gravel produced in Kansas originated from chunks of rock washed out of the Rocky Mountains, often millions of years ago, that were carried east by streams and further eroded by flowing water into small pieces of gravel or sand pebbles. Companies mine the sand and gravel by dredging river channels and floodplains, particularly those of the Kansas and Arkansas rivers, or in dry pits away from streams, most commonly in western Kansas.
When a river channel is dredged, sand is suctioned from the riverbed with a large piece of equipment called a "dredge" and moved to a nearby plant to be washed and sorted. During dredging operations on a flood plain—the area of land along the river that is inundated during flooding—a pit is dug. After groundwater fills the pit, a dredge floated on the water is used to remove sand from the bottom of the pit. Many small lakes in Kansas flood plains, especially near the Arkansas River, were dug as sand pits. In dry pit mining of sand and gravel, the sediment is removed from an excavation pit with front-end loaders and loaded into trucks.
The environmental effects of dredging have come under scrutiny in recent years. Environmental organizations, in particular, have raised questions about dredging's effect on bank erosion, water quality, and wildlife. Other concerns include the safety of canoeists and other recreational users and truck traffic and noise related to the dredging operation. The U.S. Army Corps of Engineers is responsible for dredging permits and production limits.
Crushed stone is produced mainly from layers of limestone in eastern Kansas. Small amounts are also produced from sandstone in central Kansas. Rock used to make crushed stone is mainly extracted from large open pits, or quarries, dug specifically for that purpose. The rock is blasted from quarry walls and then crushed to various sizes, depending upon what it will be used for.
Kansas Rocks and Minerals, Kansas Geological Survey Educational Series 2.
Sand, Gravel, and Crushed Stone: Their Production and Use in Kansas: Kansas Geological Survey Public Information Circular 6.