One of the key features of the new system, says Yerington, is the tri-arm variable-speed rake that aids in thickening and maintains the consistency of the mud. A pressure-sensitive gauge on the rake monitors the mud level.
As that mud level reaches a designated point, a pinch valve is activated to discharge the material. Yerington goes on to explain that a meter on the pinch valve reads the width of the valve opening, allowing the automated flocculant system to properly dose the solids again as the material enters the discharge pipe.
“Maintaining the proper mud level is so important,” he says. “The compaction of the mud squeezes out the water but if the mud level is too high, the solids will not settle out and the clean water does not go over the weirs.”
The operation is washing four different benches in the quarry. “Each bench offers a differing recipe – so we refine the flocculants that go in and we refine the speed of the rake. We might also have to adjust the mud level to get our desired results. Now that we get consistent results, the fine tuning really makes a difference,” says Yerington. He has created a spreadsheet that notes the material feed per bench, thus dictating the required operational settings of the clarification system per bench. “This allows me to properly monitor the results, making needed adjustments as we go along. We want to pinpoint the consistency even more closely,” he says.
Lamb says that Clearwater is more than an equipment and polymer supplier. “We are a business resource with the ability to analyze dirty wash water. We do a particle size distribution test and a percent of solids test to determine the most cost-effective solution for the plant. These tests will tell producers how many tons of fine sand can be recovered as a dry stackable material, and how many tons of fine silt and clay will be treated with flocculant,” he says.
It’s said that “strategic thinking is the what and why, while tactical thinking is the how.” In creating this custom-engineered system, Wendling Quarries and Clearwater Industries clearly identified the what, why and how of cost-effective wash water clarification.