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Plant Operations

M-I SWACO Bentonite Mine and Grinding Plant Operations-Greybull, Wyoming

Located in the Bighorn Basin of north Central Wyoming, this high capacity plant produces numerous bentonite products for our worldwide marketing efforts.

The mineral properties are located in Big Horn and Washakie Counties in what is known as the Big Horn Basin of north central Wyoming. For the most part, the bentonite reserves are located on Federal Mining claims that were located under the Mining Act of May 10, 1872; 17 Stat. 91, and as amended by subsequent acts. Approximately 75% of these claims have been taken to Patent, thereby giving M-I SWACO fee title to the ore. There are approximately 1,300 claims that total 26,000 acres. M-I has a minable reserve base of over 30,000,000 tons that equates out to be 1.2 billion-50lb bags so we have enough bentonite to cover your every need. The reserves have been calculated using a 4:1 stripping ratio (bank cubic yards of overburden to ton of bentonite) the average haul distance from a large portion of the reserves to the processing plant is currently fifteen miles. The bentonite beds are contained, for the most part, in the Frontier Geological formation. The various bentonite beds or seams vary in thickness from a few inches to as much as ten feet and are continuous over large areas, the quality does not vary as much as the clays in Northeastern Wyoming, i.e. Colony, Wyoming.

The bentonite beds/seams are drilled, sampled and tested prior to stripping with bulldozers and scrapers. The topsoil is removed and stored for mine reclamation before the shale overburden is removed and backfilled into a mined area. The stripped clay is re-drilled, tested for quality, field dried and marked for a particular stockpile to await hauling to the plant. Large stockpiles of clay are maintained in the mining area for haul to the plant stockpile area for blending to meet product specifications. Finally, mined areas are backfilled, then they they are contoured, top soiled and seeded with native species to comply with Wyoming Reclamation laws.

Sampling and testing is conducted throughout the mining stockpiling process. Blended stockpiles are made at the plant stockpile area by hauling and mixing various field stockpiles. The blended stockpiles are designed to product different products for different industries, i.e., Horizontal Directional Drilling, Oil Well, Waterwell and Mining drilling muds, foundry binders, iron ore pelletizing binders, feeds, civil engineering, etc. There are variations in physical properties within a given bentonite bed as well as from bed to bed. For this reason, M-I SWACO does not market a particular bentonite bed, but rather blends different bentonites to produce a product with uniform, repeatable, high quality specifications.

The plant consists of feeders, crushers, dryers, mills, air classifiers, bagging machines, bulk storage, an assortment of material conveyors, warehousing and shipping operations. The quality assurance laboratory is located at the plant for continuous monitoring of the bentonite from the mine through the milling and shipping process and a retained sample is taken from each batch/ shipment to make sure it meets the specific specs for that product. The plants present milling capacity is 650,000 tons per year. Currently, there are 127 employees who work at the plant working 6 days a week, 24 hours a day to produce some of the highest quality products on the market today.

At M-I SWACO HDD Mining & Waterwell Greybull Operation, ISO 9002 and API QI are the cornerstones of the quality system. The dual certification was achieved in 1995 and is summarized in our Quality Policy which states

We will provide products and services of consistent quality that meet or exceed the current and continuing needs and expectations of customers. The company shall strive to be competitive and produce products to specified, up-to-date, agreed-on and understood standards.

Copies of the ISO and API certifications are available upon request.

Samples of the various products produced by M-I SWACO are available upon request.

100% Owned by M-I SWACO the Greybull plant produces some of the world’s best quality bentonite products. The employees at the facility are trained in quality issues and focused on the needs of the customer to provide consistent, high quality products to the diverse and unique markets they serve.

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