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ACC - Mining and Reclamation

American Colloid Company's high-quality Volclay® bentonite is mined from shallow deposits, which occur over a broad area of the western United States.

Based on past mining experience and knowledge of surrounding underground strata, exploration crews continually locate and evaluate these deposits through test drilling.

Deposits are generally comprised of several layers and types of bentonite. Each has valuable but somewhat different properties suited to bentonite's various uses.

When a future mine site is selected, American Colloid Company's environmental specialists conduct vegetation, hydrology, soils and wildlife studies. These studies enable our reclamation team to work with area farmers and ranchers in enhancing their lands. New ponds have been added for grazing livestock, drainage patterns have improved and vegetation has grown where little had grown before.

Once permits have been secured, mining is conducted through a process known as ongoing reclamation. Using this technique, topsoil and subsoil are sequentially replaced as each new series of mine pits is opened. These shallow pits--typically measuring one to two acres in size--are opened with the aid of heavy earth-moving equipment. As the overburden--or the layer of soil directly over the bentonite--is exposed, bull dozers and scrapers work together to uncover the bentonite beds. When a pit is fully exposed, final samples are tested to ensure clay quality. A grid is also established to isolate specific clay types within a particular pit.

As mining progresses, the bentonite is extracted and topsoil and subsoil are sequentially replaced to create a suitable bed for reclamation seeding. When all of the pits have been backfilled, the soil layers are contoured to blend with surrounding topography. In the fall or early spring, American Colloid Company's environmental specialists again enter the field. During this changing of the seasons, native grasses and a nurse crop of wheat are planted to help vegetation and ground cover for smaller animal species re-establish more quickly.

From the mine site, crude clay is hauled to American Colloid Company's processing plants--in the Western region, some are as close as a mile away; others are as far as 60 to 70 miles. Once clay arrives at the plant site, it is segregated by various quality attributes and put into stockpiles. Quality inspectors direct the building and use of these stockpiles to ensure that each remains separate and free of contamination.

In its raw form, bentonite is as much as 30 percent water by weight. Because of this, rotary kilns, fluid bed dryers and other drying equipment reduce this moisture level. The drying process produces a material that is more efficient in subsequent processes of grinding, mixing and screening.

Exacting manufacturing controls at each step ensure end products that will perform uniformly and specifically to customer standards.

American Colloid Company packages its products in a variety of convenient forms, ranging from bags to bulk shipment containers.

Through its sister operations, Ameri-Co Carriers and Nationwide Freight Service, American Colloid Company maintains a fleet of flatbed trailers and vans leased to independent owner/operators to help ensure cost-efficient product transport to customers.

©2014 Minerals Techanologies Inc.