In the world of geology, "construction materials" are naturally occurring rock and sediment deposits that are used by the construction industry. Common examples of construction materials include: sand, gravel, and crushed stone, which are collectively known as aggregates; riprap (also called shot rock or rock armor), which is large blocks and boulders of tough rock used to form a foundation or sustaining wall to prevent erosion; and dimension stone, which is attractive rock that can be quarried into slabs or blocks and used for decorative construction.
Sand and gravel, which are some of the most accessible natural resources and basic raw materials, are in especially high demand. The sand and gravel industry is a major contributor to, and an indicator of, the economic well-being of the United States, by producing a high volume of basic products with a low unit value. As Alaska develops and maintains its infrastructure it is essential to have adequate quantities of sand and gravel resources for construction. In many areas of the state these materials are in short supply, are being rapidly depleted, or are not economically accessible, making it necessary to identify and characterize new resources.
Dalton Highway 274-289 project materials site, 2011. Photo credit: Alaska DOT&PF.
The Alaska Division of Geology & Geophysical Surveys (DGGS) seeks to provide information about potential sources of sand and gravel through geologic mapping projects that document the character and distribution of construction materials. Our geologic mapping and construction materials investigations are focused on areas of State-identified need, often along or adjacent to existing or planned infrastructure corridors.
Evaluating a sand and gravel deposit near Tok, Alaska, as part of the Alaska Highway Corridor project. Photo credit: DGGS.
Large-scale exploration, development, and maintenance projects will require tremendous quantities of sand and gravel for construction that could exceed the amount available from existing State of Alaska material sites. In preparation for these projects, mapping and materials investigations by DGGS provides resource information that can be used by decision makers and contractors during the planning and decision-making process.
Geologic mapping and materials investigations provide useful resource information to plan a potential large-diameter natural gas pipeline, and for infrastructure maintenance and development along this important transportation corridor.
Mapping completed by DGGS, and subsequent cooperative work with the Alaska Division of Mining, Land & Water, help identify potential sand and gravel resources to repair the Dalton Highway after damage from major flooding of the Sagavanirktok River in 2015 resulted in the critical need for large quantities for repair and maintenance.
Working with the Division of Mining, Land & Water to characterize potential sand and gravel resources along the Dalton Highway, 2015. Photo credit: DGGS.
Geologic mapping efforts near Kivalina (in progress) and Shaktoolik (completed) provide information about potential sand and gravel resources for communities facing coastal erosion problems and considering relocation.
As part of a state effort to strengthen regional and community infrastructure within the North Slope Borough and facilitate access to natural resources, DGGS is working with contractors to evaluate sand and gravel resources on the North Slope of Alaska for the Arctic Strategic Transportation and Resources Project (ASTAR). Sand and gravel is in very short supply and there is widespread interest in identifying sources of material.