During my travels as a territory sales manager for CETCO, I often hear comments about the price of bentonite. Many companies offer bentonite-based products and they have many different price points. For example, bentonite chips used to seal and decommission boreholes are offered by many companies with a wide range of prices. Not all chips are created equal! Some are a high-grade Wyoming sodium bentonite and some are mined in other areas of the country. These chips do not have the swelling ability of the high-grade Wyoming sodium bentonite. This is due to the percent of sodium bentonite versus the lesser swelling calcium type. This inferior swelling capacity leads to the use of more chips to fill a space than would be necessary if high-grade Wyoming sodium bentonite is used. Therefore, the initial cheaper price ends up more costly in the end. Inadequate swelling translates to a poor seal, and can lead to migration of surface water and containments to our groundwater.
When comparing bentonite chips, another reason why it matters where bentonite is mined is structural integrity. In a laboratory test, we used a machine to measure the force it takes to push out of a cylinder the high-grade Wyoming sodium bentonite chips, and chips found in West Texas. We found that it took 21.18 psi to push the West Texas chips out of the cylinder, which is less than half of the high-grade Wyoming sodium bentonite chips, which took 50 psi.