Hoover Materials scores natural sand source, turnkey plant

The crew was looking for limestone several years back when core drilling began at the new Hoover Materials quarry site.

Luck led to a whole lot more.

Much to the crew’s surprise, the drill detected that an overburden containing an abundance of natural sand and gravel was above the rich limestone. For this family-owned operation, the find was better than a bonus – it was more like a jackpot.

First, Hoover Materials could turn overburden into income – and that’s big. Beyond that, Hoover Materials had uncovered an opportunity to develop the only sand and gravel processing site near Nashville, Tennessee. All other sand products must be barged to the region via the Ohio River.

“Our strengths are being nimble, flexible and highly responsive to our customers,” says Tom Hoover Jr., president of the company’s sand and gravel division.

With family roots in the aggregate industry that began in the 1950s, Hoover and his father founded Hoover Materials in 2016. The company serves its market with asphalt paving services, ready-mixed concrete, crushed stone and its own trucking fleet. To boost products and services to another level, Hoover says the company was ready to take on an unexpected entry into the sand and gravel business – an expansion that ultimately led to a new turnkey-constructed plant.

Fast forward to today, and Hoover Materials is up and running its sand and gravel operation 10 miles north of Nashville near Old Hickory Lake and the Cumberland River.

“We can simply dial in product specifications, maintain consistency and meet demand, giving customers what they need when they need it,” Hoover says. “We’re seeing ongoing product growth on a sustainable site where waste is not an issue – and nearly everything is a saleable product.”

Complete turnkey plant

Last summer, Hoover Materials celebrated the commissioning of a complete crushing, screening, washing and classifying plant.

Superior Industries provided total turnkey plant construction, manufacturing all of the plant components.

“We chose Superior because they’re the only manufacturer that offers a turnkey-constructed plant,” Hoover says. “We only wanted one source to go to from start to finish – during construction, installation and for all the equipment, service and support down the road.”

According to Jason Adams, vice president of systems at Superior, a single-source approach delivers significant advantages. One such advantage is accountability to specification performance.

“Our team can fully focus on the specific application, ensuring the specs and meeting the overall goals of the operation,” Adams says. “With that focus, we can better target customized solutions that maximize productivity throughout the life cycle of the operation.”

Superior managed the process from greenfield to startup for Hoover Materials, including plant design, layout and material flow; all concrete and electrical; and all equipment manufacturing.

After the installation and commissioning, Adams says the Superior team remained on-site to “dial in” the specifications, as well as provide training. Belt Tech Industrial, a Superior dealer that’s located less than an hour from the plant, provides Hoover Materials with a local source for equipment, parts and service.

“Our processing specialists are available 24/7 for ongoing diagnostics and troubleshooting, working with the plant operator to make any needed adjustments,” Adams says. “With an internet connection, our team can remotely monitor the classifying tank, and we can log in from anywhere in the world.”

Ensuring the spec

Tom House, the quarry production manager who’s spent more than four decades in the industry, is enjoying the fruits of the plant thus far.

“In all my years, I’ve never seen such a unique processing operation with such a multitude of saleable products,” House says.

The quarry side of Hoover Materials’ operation produces a range of crushed limestone products. On the opposite side of the site, the output of the new sand and gravel operation is estimated at 350,000 tons of fine and coarse sand products each year – plus a #4 gravel and pea gravel.

With natural sand in such short supply in Tennessee, Hoover Materials focuses on an ASTM #C33 sand. Superior designed the plant to ensure that spec and more.

“After fine-tuning the plant, we’ve never had any issues at all,” House says. “Whether the feed material maintains the same gradations, or even when we’ve hit pockets of fine and coarse sand – or clay – we’ve remained right on target with our desired specs.”

In terms of processing flow, House says material is fed from a customized feed hopper to a single-deck scalping screen, then to a blade mill washer with a twin screw, before passing over a triple-deck screen with blending chutes.

“With the triple-deck screen, we separate the #4 and #8, with the small sieve sizes that pass through the bottom deck going to the classifying tank,” he says.

The 10-ft. x 32-ft. classifying tank features Superior’s Aggrespec III controls system, which automatically creates and maintains the desired specs while monitoring operating parameters and making necessary adjustments.

A Superior 600HP Valor vertical shaft impact crusher processes any oversize gravel.

“That’s an important addition, especially when we’re running our fine sands,” House says. “We can bypass the crusher for coarse material stockpiling, or we can recirculate material back through the crushing and screening circuit.”

House stresses that Superior engineered the plant to overcome all of the disadvantages of wet processing: water and material waste; stockpiling space for drying time; and costly pond maintenance.

At the wash circuit, the plant features an Aggredry dewatering washer for efficient fines management. It combines a dewatering screen with a twin wet screw, and it’s engineered to minimize water usage while capturing and reusing water resources within the system.

The dewatering screen prevents material loss, as lost fines are reclaimed in a flume and flushed back to the screw. Sand discharges from the washer with a moisture content as low as 8 percent, and it’s available as a saleable product or for additional processing.

The operation also utilizes a Spirit sand plant, which is a modular combination of cyclones, dewatering screens, sumps and pumps designed for ultra-fines recovery and maximum product output.

“It allows us to clean up our wastewater while producing plaster sand that would otherwise have ended up in the pond,” House says.

With a plant that delivers multiple products, maintenance ease and sustainability, Hoover Materials is maximizing productivity and profitability.

“I’ve never seen anything go so smoothly – even during a very rainy season,” says House, referring to the turnkey construction process. “It’s the people, the partnership and the communication that has made this project so successful.”

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Carol Wasson is a veteran freelance writer for the aggregate and construction equipment industries.