Precision Aggregate Products, LLC is a producer of high-quality ready-mix and other aggregate products. With a permanent plant based in Mesquite, Nev., and three portable plants, Precision Aggregate supplies the Las Vegas and northwestern Arizona markets with concrete sand for the construction of roads, bridges, boat launches, wastewater treatment plants and more.
Case Studies
Challenge
At their permanent plant in Mesquite, Precision Aggregate washes, classifies and dewaters C-33 concrete sand and golf course sand with a screw washer and dewatering screen system.
As is typical for many aggregate wet processing plants, the waste stream at Precision Aggregate — which includes the overflow from the screw washer that contains the water and fine particles, as well as the water and fine particles that pass through the dewatering screen — is directed to a settling pond.
Settling ponds allow for the separation of fine particles from the liquid in a slurry. Over time, the solids suspended in the liquid settle to the bottom of the pond, resulting in clear water that can be reused in the washing process.
However, the settled solids need to be removed from time to time to make room for additional material, and the process of cleaning the pond can be both time-consuming and expensive.
Precision Aggregate’s settling pond would fill up quickly, and they would have to remove the solids from the pond regularly. They wanted to find a way to reduce the volume of solids reporting to their pond to reduce the frequency with which they had to clean it out.
Solution
Precision Aggregate turned to Kimball Equipment, McLanahan’s dealer in Nevada, for a solution. McLanahan and Kimball worked with Precision Aggregate to size an UltraFINES Recovery (UFR) system to meet the specifications required of the application.
“We put in the UFR system to help us so that we didn’t have to clean out the ponds so much, to help get the fines out of the pond, and to help keep our ponds clean to help us run longer throughout the day,” explained Scott Woods, who oversees the wash plant at Precision Aggregate.
McLanahan UFR systems recover nominally +400 mesh solids and produce a drip-free material. These systems consist of a bank of Hydrocyclones (four in Precision Aggregate’s configuration), a Pump, Sump and Dewatering Screen.
At Precision Aggregate, the waste stream from the wash plant enters the UFR’s Sump and is pumped to the Hydrocyclones. The Hydrocyclones separate the fine material from the liquid portion of the waste stream and discharge it onto the Dewatering Screen. The Dewatering Screen removes excess moisture from the material and discharges it in a drip-free state that is easily conveyable and stackable.
Removing this fine material out of the wash plant waste stream reduces the amount of material bound for the settling pond and helps to keep the pond from filling up too quickly.
Results
Although there was a bit of a learning curve with the system at first, McLanahan and Kimball were available to provide Precision Aggregate with the support they needed every step of the way, and the McLanahan UFR has been running smoothly since startup.
“It was a little different because we had never run one, but once we got it up and running, it turned out to be pretty good,” Woods said. “It works great.”
Woods said the UFR is simple to operate.
“We turn it on, it runs pretty much all day. We haven’t had really any issues with it,” he said. “It’s been a pretty sound system. It runs great. It does a great job for what we need.”
Before Precision Aggregate installed the McLanahan UFR system, Woods said they were cleaning out their settling pond quite frequently. Now, with the addition of the McLanahan UFR, Precision Aggregate has cut their pond maintenance by over 60%.
“The UFR system, the thing I like the best about it is that we don’t have to clean our pond so much,” Woods shared. “It keeps all the fines out of the pond.”
Not cleaning out their pond as frequently has allowed Precision Aggregate to reduce wear and tear on their equipment as well as to reduce the amount of time that is spent removing the solids from the pond.
“We’re not wasting valuable time dredging the pond and wearing out our excavator doing it,” said Woods. “Now, we’re cleaning our pond once a day, and it’s a lot less time and wear.”
