Conveyors cover a lot of ground…no pun intended. There are many different types of conveyors that perform different tasks in a quarry, but they all move material from one place to another. Conveyors can stack material; bring it up out of a pit or underground operation; cross over or under a roadway, railway, or river; or travel the length of the pit floor. Of all the different types, overland conveyor can have the biggest impact on an aggregate operation.
“Typically, overland conveying is the alternative to haul truck operation,” says Alan Schmidgall, inside sales manager for Superior Industries. “Basically, an aggregate operation has a mine face and a processing plant, but the face is always moving as the rock is blasted and picked up. As the crushing gets farther away from the plant, the material has to be transported from the blast site to the processing plant.”
Some operations use haul trucks or loaders to transport material from one place to another, but many use overland conveyors. The overland conveyor is capable of moving material much quicker, easier, and more efficiently than mobile equipment, and greatly reduces the amount of time, money, and manpower required.
“Overland conveyors move material for much less money than loaders do,” says Jay Mills, site superintendent at Staker Parson’s Reynolds Pit #2 in West Valley City, Utah. “They’re cheaper to run, and move material faster and more efficiently. Using a loader to move material cost us about 75 to 80 cents a ton. Once we put in the overland conveyor, it cut the cost down to about 12 to 13 cents a ton. That’s a huge savings.”
Robert Hostettler, plant manager at CalPortland’s Santosh Facility in Scappoose, Ore., says overland conveyors allow operations to keep closely connected with the mining portion of the operation as it moves further away from the processing plant. “Extending the pit line makes it possible to maintain a minimal haul distance between the material extraction point and the feed hopper,” he says. “The distance can be decreased by adding more overland conveyors, thus minimizing the haul.”
In addition to cost savings, overland conveyors don’t require as much maintenance and have a much smaller impact on the environment when compared to mobile equipment. There are fewer items that can break or need repair on a conveyor, since they are most commonly comprised of motor(s), gearbox(es), one head pulley, one tail pulley, a take-up, idlers, bearings, and a belt. Plus, the conveyor is powered by an electric motor or motors, which means fewer emissions, little fuel consumption, and less noise. This is good for the environment and helps maintain a good relationship with neighbors as well, making it a win-win situation for everyone.
Alan Schmidgallbegan working at Superior Industries after graduating from the North Dakota State College of Science in 2005. He started out in the engineering department, moved to project management, and now manages the manufacturer’s team of equipment inside sales personnel.
Robert Hosteler is the plant manager at CalPortland’s Santosh Facility in Scappoose, Ore. He began his career with Triangle Rock Products in Oroville, Calif., after graduating from California State University, Chico, in 2011 with a bachelor of science in Concrete Industry Management.
Jay Mills is the site superintendent at Staker Parson’s Reynolds Pit #2 in West Valley City, Utah.
Voices of Experience
Overland conveyors provide an economical and efficient way to move material from one place to another, says Alan Schmidgall, sales manager for Superior Industries. “The overland conveyor, in the traditional sense, is much more economical than haul trucks,” he explains. “It offers a more stable, lower cost-per-ton option to carry material the same distance as a haul truck, and one operator can run the entire system.”
Schmidgall says maintenance offers another plus for overland conveyors. Haul trucks are expensive, requiring the replacement of wear parts and tires, as well as general maintenance. Maintenance costs for an overland conveyor, however, are much lower and much more predictable.
When it comes to the length of an overland conveyor, Schmidgall says the sky is the limit. Most are 250 to 1,500 feet long, but some can be several miles long. It depends on the application.
Sometimes material must be moved across a highway. “We’ve done a few of those installations,” Schmidgall explains. “The conveyor goes up, spans the highway, and goes back down on the other side. We use a covered or contained conveyor system, so any spillage is captured.”
Most overland conveyors are custom built, requiring topographical information and a design suited to the individual application. Schmidgall says the development costs for those types of conveyors aren’t prohibitive, but the design takes time and so does the installation. So, Superior developed the Zipline conveyor, a more standard off-the-shelf design that installs easily and has the flexibility to adapt to the needs of a site.
“The focus with the Zipline conveyor was to make a lower cost, pre-designed modular overland conveyor that was quick and easy to install,” Schmidgall says. “However, if you’re going to be at the same site doing the same thing for 20 years, the heavier traditional overland conveyor designed for the specific application is probably still the best option.”
“We have roughly 2 miles of overland conveyors running from our material extraction point to our processing plant,” says Robert Hostettler, plant manager at CalPortland’s Santosh Facility in Scappoose, Ore. “We run 48-inch belt on all of the conveyors in our pit line, which can handle between 1,000 and 1,200 tons of material per hour. There are four main benefits for using overland conveyors — environmental impact, cost savings, manpower savings, and efficiency/ throughput.”
When it comes to being “green,” overland conveyors are powered by electric motors as opposed to diesel-powered trucks. “There’s a smaller operational foot print with overland conveyors,” Hostettler says. “While transporting material from point A to point B, the electric motors release far less harmful chemicals into the air than do diesel engines. Plus, many of the conveyor components — idlers, pulleys, belting, motors, and gear boxes — are able to be recycled or reused in other parts of the plant when they are removed from the pit line.”
Hostettler says cost savings are realized in several ways. Electric power is more cost efficient and more stable than diesel, and is less affected by market trends. Plus, maintenance on overland conveyors is less labor intensive and less expensive than maintaining mobile equipment wear components.
“Many conveyors are automated and interlocked so that one operator can run the entire pit line safely, regardless of length, with just the push of a button in the switch house,” Hostettler says. “That eliminates the need for multiple operators on site to run the pit line. So, you get a labor cost savings there.”
If you compare truckz to using overland conveyors with capacities in excess of 1,000 tons per hour, Hostettler says, “It would require multiple trucks, operators, etc. to achieve a similar throughput,” Hostettler explains. “Overland conveyors are much more efficient over all, and their capacities are greater.”
According to Jay Mills, site superintendent at Staker Parson’s Reynolds Pit #2 in West Valley City, Utah, overland conveyors are cheaper to run than mobile equipment; are better than regular conveyors because they only have one gear box, one tail pulley, and one head pulley; and are way more efficient to operate.
“That’s the reason we put them in at this particular location,” he says. “By using two overland conveyors, we were able to get rid of one of our loaders. Overland conveyors are amazing, and if you put a stacker on the end of them, it’s paradise. It’s a huge savings.”
The long overland conveyor belts are easier to train and keep centered on the conveyor than shorter belts, Mills says. The only drawback he sees is that, if the overland belt gets ripped, it costs a lot of money to replace it.
“I am way sold on overland conveyors,” Mills says. “Anywhere you need a long conveyor, that’s definitely the way to go. There’s no negative. We recently installed a Zipline conveyor at this plant. We’ve used other overland conveyors before, but the Zipline can be installed in about half the time it takes to install traditional ones. It’s very fast. If it holds up, I’ll suggest it for all of our similar operations, because it is so fast to put in.”
Mills says the only difference between a traditional overland conveyor and a Zipline is that the traditional one takes longer to set up. The easy assembly of the Zipline is a plus, but he doesn’t think the Zipline will be any different than the traditional ones in the long run.
One thing that can help an operator determine which overland conveyor to use is the length needed. The maximum length of a Zipline conveyor is 500 feet. “That’s perfect here, because I’ll never be far enough away from my material that I’ll need anything longer,” Mills says. “If you can get by with 500 feet, the Zipline is the way to go, but if you need it to be longer, it would be worth the extra week it takes to install the traditional overland conveyor.”