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Caldwell Stone’s tailgate upgrade improving productivity

By |  February 19, 2020
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To achieve full utilization without risking public safety, Caldwell Stone management turned to Philippi-Hagenbuch to provide a custom-engineered solution that ultimately increased capacity on its Volvo A40D articulated hauler up to 17 percent per load, while heightening user safety. Photo courtesy of Philippi-Hagenbuch

Maximizing productivity is the universal key for a healthy, successful business.

What that looks like for each business varies, but every owner, manager and general employee can attest to the fact that if things aren’t running as smoothly as possible, the business is losing money somewhere. Identifying productivity bottlenecks and taking steps to correct them can take a business from good to growing.

For Caldwell Stone Co., a Kentucky-based crushed stone producer, underhauling aggregate from its site to neighboring plants was eroding overall productivity – and limiting the company’s potential. To achieve full utilization without risking public safety, Caldwell Stone management turned to Philippi-Hagenbuch, a longtime partner, to provide a custom-engineered solution that increased capacity on its Volvo A40D articulated hauler up to 17 percent per load, while heightening user safety.

Ready for the next century

With more than 100 years in the same location, Caldwell Stone has seen its share of market evolutions and innovations.

The company was established in the limestone-rich hills just outside Danville, Kentucky, as Taylor Brothers’ Quarry in 1912. In 1929, W.P. Caldwell purchased the operation and renamed it. Quarry operations focused on extracting and crushing stone, leaving room for a block plant, ready-mix plant and asphalt plant to take root nearby.

In 1972, upon Caldwell’s death, majority ownership passed to D.K. Albright, and in 1984 the Albright family took over 100 percent ownership. Now in the hands of the third generation of the family, management continues to adhere to the same high standards of quality and reliability set by Caldwell, seeking out the tools and innovations that will allow the quarry to continue serving local construction and residential contractors for the next 100 years.

“A lot has changed in the aggregates industry over the past 100 years, but for Caldwell Stone, one thing has remained constant: our dedication to our community,” says Clay Albright, vice president of Caldwell Stone. “We keep our quality standards high because we know the materials we supply to neighboring plants are destined for jobsites and projects throughout our region. With everything we do, we strive to make our process as safe, reliable and efficient as possible, allowing us to continue serving this community.”

Blacktop worries

Delivering crushed aggregate directly to nearby plants is one area in which Caldwell Stone has found itself uniquely positioned to serve the local community.

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For more than two decades, the quarry’s main pit truck – a Cat 769D rock truck – relied on a Philippi-Hagenbuch Autogate tailgate to maximize productivity. Photo courtesy of Philippi-Hagenbuch

With several plants in close proximity, the quarry developed its own hauling network and makes daily deliveries of construction aggregate, crushed stone, base stone, riprap, round gravel, aglime and fines to customers in a 30-mile radius.

To maximize productivity on the short haul from the stockpile to neighboring asphalt and cement plants, Caldwell Stone uses its off-highway, articulated dump trucks, including a 40-ton A40D Volvo. This trip always came with increased risk because it involved crossing a county highway and immediately climbing a slope on the opposite side. With a full load, there was the possibility of spilling aggregate on the public roadway – endangering customers and neighbors.

“Even though we’ve never had a spill, it is a constant worry,” Albright says. “We take our responsibility for public safety seriously. Aggregates on the road could cause damage or worse, an accident. That’s something we want to avoid at all costs. We’ve swept up after other contractors, too, just to make sure the road is clear for motorists.”

To minimize the risk of spills, Caldwell Stone tried equipping its trucks with low-cost tailgates. When these failed to live up to the demands of the process, management opted to under-fill trucks in an effort to safely continue providing off-site services.

Albright estimates the company’s A40D Volvo articulated dump truck routinely ran loads that were 5 to 10 tons under capacity. On an average 500-ton delivery, underhauling accounted for three to five more trips than necessary, resulting in a significant loss of productivity and revenue.

Custom-engineered solution

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The precise fit of the new tailgate means materials are completely contained during loading and transport, allowing Caldwell Stone to confidently fill the truck more uniformly from front to back while increasing loading speed and reducing downtime. Photo courtesy of Philippi-Hagenbuch

Tailgates were not a new solution for Caldwell Stone. In fact, the quarry had seen amazing results from one OEM model.

For more than two decades the quarry’s main pit truck – a Cat 769D rock truck – relied on a Philippi-Hagenbuch Autogate tailgate to maximize productivity. Despite daily beatings in the pit, the tailgate’s only major damage resulted from a collision.

“A driver tried to pass a dozer on a narrow section of the haul road and the outrigger caught the blade,” Albright says. “That’s the only time we’ve had to order parts for the PHIL tailgate. Other than that, we’ve never had a problem. It’s beyond durable.”

Other tailgates, however, haven’t produced the same results. Over the years, Caldwell Stone equipped its Volvo dump trucks with tailgates from other manufacturers. These tailgates failed to provide the same level of dependability, though.

Bent frames, broken welds and snapped cables were a common occurrence. At first, the quarry did its best to repair the damage done by shifting rocks. But, eventually, maintenance and repair costs outpaced any productivity benefits, and Caldwell Stone removed the tailgates from its dump trucks.

“We’d seen what a high-quality tailgate could do for productivity, so we knew it was possible to safely haul at capacity,” Albright says. “We just needed to work with the right manufacturer this time. The previous products were inferior – they just didn’t have the same durability. This time we were working with PHIL. No questions.”

Caldwell Stone reached out to Philippi-Hagenbuch in late 2018 to outfit its A40D Volvo articulated dump truck with an Autogate tailgate. To ensure a proper fit, PHIL engineers worked with quarry staff on precise measurements.

In addition to the make and model of the truck, Caldwell Stone provided detailed measurements of the truck bed, as well as specifics on the material it intended to haul and the condition of their haul roads.

“PHIL offered transparent and consistent communication during the entire process,” Albright says. “To fabricate a tailgate for our specific truck, the PHIL engineers wanted to know everything about our operation – not just measurements, but what we were hauling, where we were hauling it. I never expected there to be that much difference from one bed to another, but the PHIL team made sure our tailgate would fit down to the millimeter and stand up to whatever we put it through.”

Caldwell Stone’s tailgate shipped from PHIL’s Peoria, Illinois, campus and arrived at the operation in early 2019. A PHIL engineer assisted with installation as part of the terms for the product’s three-year warranty.

“We were more than a little impressed,” Albright says. “For a machine that hauls literally tons of material, the attention to detail to create a near-perfect seal was simply amazing.”

Precision pays off

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In 2018, the Volvo A40D averaged 31.48 tons per load, making more than 1,000 trips to the asphalt and ready-mix plants across the highway. Since adding the tailgate, the Volvo averages 36.7 tons per load – a 17 percent increase over 2018 numbers. Photo courtesy of Philippi-Hagenbuch

With the addition of the tailgate, the Volvo A40D became the quarry’s primary hauling vehicle.

“It’s one of our newer trucks, so the employees always preferred it,” Albright says. “But with the tailgate, it’s become the de facto haul truck. They don’t have to worry about spilling when they cross the road. It’s made hauling a lot less stressful and far more productive.”

In 2018, the Volvo A40D averaged 31.48 tons per load, making more than 1,000 trips to the asphalt and ready-mix plants across the highway. Since adding the tailgate, the Volvo averages 36.7 tons per load – a 17 percent increase over 2018 numbers.

“Depending on the material, we are able to get maximum capacity without fear of spilling,” Albright says. “The tailgate has really helped us optimize our productivity and increase profits several thousand dollars in less than a year.”

In addition to larger loads, Caldwell Stone is finding some unexpected benefits from the tailgate. Agricultural lime has always been one of the quarry’s more popular products, but transporting the highly flowable material presented a challenge.

“It’s like water pouring out of the bin,” Albright says. “Before the tailgate, we were significantly underloading our trucks to keep the aglime from just flowing out the back when we were hauling it.”

The precise fit of the new tailgate means the aglime is completely contained during loading and transport. Knowing the load won’t spill also allows Caldwell Stone to fill the truck more uniformly from front to back, increasing loading speed and reducing downtime.

According to Albright, the durable steel construction and simple, user-friendly design minimizes maintenance, as well. This is a relief for Albright, who remembers the continuous maintenance required on the previous tailgates.

“Everything about it is easier,” he says. “It’s the product we needed to take us from good to great in terms of productivity.”

Partners for the long haul

Identifying and working with the right partners to correct inefficient processes has kept Caldwell Stone moving forward for more than 100 years.

As management looks to the next 100, Albright sees new potential in the renewed partnership with Philippi-Hagenbuch.

“No one knows exactly what the future of American quarries will look like,” Albright says. “But I know working with manufacturers like PHIL means we’ll be able to meet changes head on – with the right tools and support to maintain the high-quality standards Caldwell Stone’s reputation is built on.”


Arielle Windham is a writer for the aggregate, mining and construction industries.


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