Upgrading its screening circuit increased throughput and improved material separation for Minnesota’s McNamara Contracting, after installing a triple-deck horizontal screen from McLanahan.
As one of the longest-established original equipment manufacturers in the quarrying and aggregates sector, McLanahan Corporation has spent more than 190 years developing processing solutions.
Over time, its crushing and screening equipment, supported by an extensive dealer network, helps quarry and aggregates operators produce materials for America’s infrastructure, roads, and more. Its proven designs consistently meet the challenge.
Now its history in creating field-ready solutions is helping McNamara Contracting increase production at its operation in Minnesota. McNamara Contracting, a third-generation contractor in Rosemount, Minnesota, supplies aggregates for asphalt and base, and offers civil construction services. The Minnesota-based business needed to upgrade its screening equipment after the shaft and bearings on its previous screen deck failed, prompting the contractor to seek a more dependable, higher-capacity screening solution.
Looking for a replacement, McNamara rented a triple-deck horizontal screen from Viking Aggregate Equipment, the manufacturer’s regional dry processing dealer. The dealer supported the installation and commissioning of the screen, ensuring the unit was tuned for the application before production began.
The triple-deck solution features McLanahan’s triple-shaft mechanism with an aggressive oval stroke, adjustable settings, and an end-tensioned bottom deck for easy maintenance, with access holes for screen media replacement.
The unit was installed on a portable chassis and includes wide walkways, dual-access ladders, and a sliding discharge chute to improve access and simplify maintenance.
The horizontal screen was installed as the final screen in the crushing circuit, separating material from the primary and secondary crushers into three final products used in McNamara’s asphalt mix.
“It handled a lot more material, and just the way everything was set up on it with the sliding chute and the accessibility to get to the screens, everything worked really well with that screen deck,” McNamara crusher operator Joseph Adelmann said.
Material too large to pass through screen openings moves along the screen to discharge onto the product conveyor. Oversized material is returned to the crusher for further reduction until it passes through the screen and is sent to the stockpile.
Material is fed onto the screen decks where it is separated by size as it moves across the screening surfaces.
Oversized material that cannot pass through the screen media is discharged and returned to the crushing circuit for further reduction before being processed again.
Since introducing the horizontal screen, McNamara has seen an increase in both production capacity and screening performance compared with its previous unit.
Adelmann said the new screen allows the operation to process a higher volume of material while maintaining product quality.
“It shakes a lot more to where it’s able to sift a lot more and handle a lot more material to where we can put more out,” he said.
The improved screen capacity has also enabled the operation to upgrade other parts of its processing circuit to support higher throughput.
“Since the horizontal screen is able to handle more, we were able to get a new conveyor that could pour more material to that screen deck, so we’re not wasting space,” Adelmann said.
Maintenance accessibility has also been a major improvement compared with the company’s previous screening unit.
The horizontal screen features an end-tensioned bottom deck, designed to simplify screen media replacement.
The sliding discharge chute also allows operators to quickly access the screening surfaces for maintenance.
McNamara has already replaced the screen media on the bottom deck twice since installing the machine, and Adelmann said the process has been significantly easier than with the contractor’s previous screen.
“Our last screen, you had to unbolt a hundred-pound plate at the end and put that off to the side, and that’s how you got into the screens,” he said.
“It’s really nice to slide that chute back to where you can get in there and get everything, and then I really do like the end-tensioned screens.”
In addition to simplifying maintenance tasks, the machine’s design has improved safety and accessibility around the screening unit.
Wide walkways and ladders on both sides of the screen make it easier for operators to carry out inspections and service work.
Adelmann said these practical features have made a noticeable difference for the team operating the plant.
“Everything is way nicer with the McLanahan Horizontal Screen,” he said.
With increased throughput, improved separation performance and easier service access, the triple-deck horizontal screen has become a key part of the contractor’s portable crushing and screening operation. AB
