Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/632397
AGGREGATES MANAGER / February 2016 39 APPLICATIONS need a pit, have set up costs, or need to be permitted." According to Clark, when building remote gravel roads, the cost of hauling in gravel can quickly escalate the cost. "The farther away the road from the pit, the higher cost; and the more remote the road, the fewer the pits," Clark says. "That's when your price per mile of grav- el road goes through the roof. "Fortunately, with a linear crush- er your price stays constant," he adds. "Without the material hauling cost, it costs the same per mile." This allows the linear crusher to do remote projects for the same price as a local project. Better roads for less According to Clark, the linear crusher has performed well for customers that require building or maintaining good gravel roads at lower cost. He says that, for years, a timber company in St. Maries, Idaho, had been struggling to keep a steep, 2-mile stretch of single-lane gravel road in shape with traditional blading and dust abatement. "For heavy logging truck use, the consistent 15+ road grade was challenging, the road profile was off, the aggregate was loose, and a big outcrop of rock near the top of the hill required lifting the road profile to go up and over it," Clark says. "There weren't enough fines in the road to bind the aggregate together, so dust abatement didn't work very well." The traditional approach to address the challenge would be to haul dirty gravel onto it, but that would have been costly — about $35,000 per mile of lane including dust abatement, according to Clark. Instead, Roadtech did the rock hammering, proper grader work, then used the linear crusher to break down oversized material and blend in the fines. "With the linear rock crusher, we were able to get the fines back in so dust abatement would hold in better," Clark says. "They've been running on that road for three years now, and it's holding up beautifully for them." Improved road repair Roadtech has found that the linear crusher also cost-effectively performs gravel road repair in Ferry County, Wash. According to Clark, traditionally, the county only bladed many gravel roads with a grader because they lacked the funding to re-gravel them, and a grader's capabilities are quite limited. "Traditionally, with a grader, when you pull out large rocks, it makes a mess. You'll never get it compacted right again, and you'll get ruts forming in your road," Clark explains. "After pulling out the large rocks, you have to cast them over the side of the road, which widens your road and costs more to maintain." As an alternative, the county now runs its own grading crew, and Road- tech follows with its linear crusher. "We can typically re-gravel and rehabilitate from 2 to 6 miles of gravel road for essentially $36,000 per week, plus crew cost," Clark says. "With the traditional way of burying the problem, it would cost over $100,000 a week for a similar project." According to Clark, this approach has allowed Ferry County to put in a new maintenance protocol for their roads. "The linear crusher allows the county to work on roads they would normally have to wait five to 10 years to re-gravel," Clark says. Clark explains that the county not only gets to reuse the material on the road, but also gets to correct the road. Essentially, this allows the county to pull the big rocks out, and use the grader to actually correct the road. This improves the road profile and water drainage, which lowers road maintenance costs, so they don't have to blade it as often. "On a typical county road project, you'll save roughly $15,000 per lane mile, plus about $2,500 per year per lane mile in gravel road maintenance," Clark says. "With proper subgrade preparation, instead of burying the problem, you can gain an additional three to five years of road life. A linear crusher can also decrease how frequent- ly you do general blade maintenance by about 50 percent." AM Del Williams is a technical writer based in Torrance, Calif. A linear crusher moves along the road as it windrows together oversize rock, existing rock and gravel, and natural fines in one pass.