Top-Rated Producer Stresses Performance & Safety
As the largest and oldest producer of crushed stone in Oklahoma, Dolese Bros. Co. prides itself on a legacy that began more than a century ago. Today, Dolese maintains a full-service construction supply and material operation that employs over 1,000 skilled workers. The company also operates six crushed stone facilities, four sand plants, one sand and gravel plant throughout Oklahoma, as well as a sand and gravel operation in Louisiana. Dolese is repeatedly recognized for its leadership in the areas of quality, safety and environmental dedication; and is consistently ranked as one of the top 20 aggregate producers in the country.
To support its ongoing quality mission, the Dolese management team is continually evaluating and implementing strategic upgrades within its facilities to improve performance, safety and customer service. Among its many initiatives, Dolese recently decided to install new crushing systems at two of its limestone quarries. According to plant operations personnel, the company wanted to take advantage of the latest advances in crusher design – namely, the safety and productivity-focused hydraulic systems in the new jaw and cone crusher models.
At its Ardmore Quarry, Dolese installed a Telsmith 3244 Hydra-Jaw Crusher to replace an older jaw; and a Telsmith 52SBS Cone Crusher to replace an older vertical shaft impactor. At its Hartshorne Quarry, older crushing units were replaced with two Telsmith Cones – the 44SBS and the 57SBS. “Our new crushers allow far safer operation, while also allowing us to increase product quality and decrease maintenance downtime,” says Melvin Barks, plant superintendent at the Hartshorne Quarry. Barks was initially involved in the selection and installation of the new equipment; and worked closely with the Telsmith engineering and sales team, and the onsite service technicians. “With all four installations, we had Telsmith service technicians assisting us. They were phenomenal. One of the service mechanics even helped us take the old jaw out, and he wasn’t even required to do that,” says Barks.
Plant Superintendent Terry Smith oversees the equipment at the Ardmore Quarry. “Our previous, older jaw would often jam up, especially during power outages. We would have to get in there and manually dig it out with sledge hammers and shovels, or with an extendable forklift. That’s time consuming and risky,” says Smith. “If tramp iron went through the old jaw, it would lock up and again, we would have to get in there and get it out – and there are safety issues with that. With the new Hydra-Jaw, the jaw automatically clears itself. With the push of a button, it will discharge the materials and resume to its former settings, and we’re back to crushing,” he says.
Consistent with prior Hydra-Jaw models, the H3244 incorporates an advanced hydraulic toggle which is not available on traditional jaw crushers, say Telsmith engineers. It provides the advantages of hydraulic tramp iron relief, chamber clearing and setting adjustment. This new technology allows operators to clear the chamber or adjust the setting from a control house or remote location, using push button controls. Importantly, in addition to delivering greater uptime availability and production capacity, these hydraulic systems eliminate the need for maintenance personnel to climb into or under the jaw.
“Anytime you have to get inside that jaw, there is a potential safety hazard. When you can take care of clearing the jaw with a hydraulic system, that is a safety plus,” says Barks.
The hydraulics in modern jaw designs are integral to fast, safe toggle maintenance, say Telsmith engineers. As to the Hydra-Jaw, the process is initiated by hydraulic adjustment cylinders that push the pitman forward where it is locked into position with lock-out pins which insert from the side. Then hydraulic tension cylinders, mounted on the side of the toggle, pull the toggle beam back, allowing it to be safely lowered away. Toggle lifting eyes assist in safe, speedy toggle removal.
Note that older jaw designs would often require that the pitman be held forward with chains and a winching device that is not always easy to secure. Also a worker would be required to climb under the jaw to remove the tension assembly before the toggle could be lowered – a risky task that puts the worker directly under the loose toggle. Modern jaw designs eliminate the need for workers to go under the jaw until after the loose toggle is safely lowered.
Another downside to older, conventional jaws, says Barks, is the amount of downtime incurred when trying to change the closed-side setting. “From start to finish, it would take up to three hours. We had to shut down, loosen a plethora of bolts, pull the jaw together, put shims in it and put the bolts back in. It was such a time-consuming process every time we wanted to change products,” he says. “With the new jaw, we can make adjustments frequently, and can increase the production of a wide range of products,” adds Barks. He explains that Telsmith has designed the jaw so that the operator can adjust the crusher in just moments using the hydraulic control panel. No spring adjustment, shim adjustment or tools are needed.
After the successful installation of the Hydra-Jaw, Dolese decided to upgrade their secondary circuits with the Telsmith SBS Cones. Barks says that the 44SBS was purchased to reduce wear costs incurred by a previous VSI. “The rock at the Hartshorne Quarry is a very abrasive limestone and we were changing VSI shoes about every three days. Wear costs were astronomical. After approximately 18 months, we’ve changed the liners on the SBS only twice,” he says. “We replaced our older cone at Hartshorne with the 57SBS Cone, which gives us a high-quality cubical product. With the previous cone, we were experiencing too much flat and elongated rock – and that is becoming a big issue with the Oklahoma DOT,” he says, adding that at the Ardmore Quarry, a 52SBS was chosen to replace a VSI that was creating an overabundance of fines.
“When you look at these new crushers as compared to those of decades ago, you’re talking Fred Flintstone,” says Barks. With today’s competitive environment, it has never been more important to consider the performance and safety advantages of modern crusher designs.