There’s more to operating a gravel pit than meets the eye.
A gravel pit is a type of open-pit mine used for the extraction of sand and gravel (aggregate) from a deposit near the surface of the earth. Sand and gravel serve a variety of purposes across a whole bevy of industries, including in the mixing of concrete for road surfacing and in the production of other construction-related materials.
The Seven Stages of a Gravel Pit
Developing and maintaining a gravel pit is a multistep process, as the Department of Indigenous and Northern Affairs Canada (DINAC) attests. In a report entitled “Understanding the Sand and Gravel Business,” the DINAC explains that the aggregate extraction process takes place in seven stages: exploration, regulatory approvals, financing, site preparation, extraction, processing, and site rehabilitation.
In the exploration stage, field search and measurement activities are conducted in order to assemble information on the location, size, quality, and nature of the particular gravel and sand deposit to be mined. Any published geologic information pertaining to the prospective site is examined in order to assess the location’s sand and gravel potential. Next, a geologist should visit the site in order to review local land features and identify areas that may be particularly hospitable to a gravel pit.
The goal of this research is to determine whether setting up a gravel pit in the location in question will be cost- and time-effective. If the field surveys prove favorable, more intensive geoscientific studies — such as test pitting, geophysical surveys, and geological mapping — can be conducted to further ascertain details about the volume and quality of sand and gravel deposits in the specified location. In some cases, test drilling might be needed following this research to determine the depth and area of a particular deposit.
After exploration, the next step for developers is to secure all of the necessary regulatory approvals and financing for the project. Then, before any extraction of sand and gravel can occur, the site’s safety and efficiency must be verified. This site preparation entails clearing trees, removing topsoil, installing fences and gates around the pit location itself, and potentially constructing culvert pipes, ditches, and collection pools to drain surface runoff and prevent erosion.
Finally, extraction can occur. Backhoes, front-end loaders, and bulldozers are all used to pull the gravel and sand from the pit. Before the extracted material can be sent off to the customer, it must undergo processing; this involves screening for large rocks, crushing, sorting, washing, and stockpiling the extracted material.
Site rehabilitation is the critical last step, and consists of slope reduction, spreading stockpiled topsoil over the mine site to encourage revegetation, and removing all garbage, supplies, and equipment. There are a range of possibilities for reusing the grave pit site post-extraction — including housing, parks, or for commercial development.
Clearly, site operators must consider a wide range of factors when developing a gravel pit — so on-site dust management should be kept as simple as possible. Midwest Industrial Supply, Inc. keeps transport roads in good condition with environmentally-friendly and cost-effective products and solutions that suppress harmful PM10 and PM2.5 emissions and stabilize and strengthen road surfaces.
Similarly the application of Midwest’s line of material handling dust control solutions — including the Dust-Buster® Foam System — in processing areas ensures that dust is kept in check through every step of gravel extraction and processing, from the conveyor belt to the storage pile.