Interstate Anniversary Convoy NV
July 24, 2006 www.acppubs.com
Edition serving Arizona, New Mexico, Colorado, Utah, Wyoming, and Nevada since 1925
Rock Trenching FOCUS: Aggregate Production
Precision Trenching & Drilling cuts through rock in Colorado mountains for new Pinewood Springs water lines By Hol Wagner
P
inewood Springs is a tiny mountain community nestled among the peaks along either side of US-36 between Lyons and Estes Park, the eastern gateway to Rocky Mountain National Park. Two years ago the village was threatened by a wildfire that burned through the bone-dry
forest to within two miles of the northwestern edge of town. Fortunately, the blaze was contained in time, and Pinewood Springs was spared. Hot, dry summers can be the bane of mountain living, and in fact another fire broke out on the southeastern outskirts of Pinewood Springs as a homeowner burned debris on his property the day Rocky Mountain Construction visited the community. Happily, it, too, was quickly extinguished. This spring, with many residents only weeks away from having to haul potable water to their residences, the Pinewood Springs Water District has completed a new storage reservoir and a 7,900-foot pipeline linking the reservoir with the town’s water treatment facility beside the Little Thompson River. Actually, two pipelines were installed in the same trench: a supply line to deliver raw water to the reservoir from the river, and a smaller domestic water line to deliver reservoir water to the treatment plant. The two lines should eliminate any treated water
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July 24, 2006
ROCKY MOUNTAIN CONSTRUCTION
shortage this year – and well into the future. Approval to construct the water lines took over two years and cost in excess of $40,000, however, due in large part to the presence of potential Preble’s meadow jumping mouse habitat near the river. In a rush to get the work completed, the water district sought bids on the project and got four offers. Three of the bidders proposed to drill and blast their way through the rocky path of the pipeline in order to produce the needed trench, hauling in select backfill to surround the two ABS waterlines and using a portion of the excavated material to fill the remainder of the trench. The fourth bidder, Temple Construction Co. of Fort Collins, Colo., submitted an offer some $200,000 lower than the others and was quickly awarded the contract for approximately $700,000. The secret to Temple’s winning bid: trenching through the rocky terrain rather than drilling and blasting. Temple had worked before with Ron Johnson, owner/operator of Precision Trenching & Drilling of Broomfield, acppubs.com
Far left and left: Precision Trenching & Drilling’s Tesmec TRS-1100 rock trencher works its way down Kiowa Road in Pinewood Springs, cutting 6.5 feet of 6.5-foot-deep trench per minute for new water lines. The ABS pipe, pre-fused into long strings, is already laid out along the path of the trench, ready for installation. Photos by Hol Wagner Below: The big Tesmec trencher produces a fine spoil that can be used as bedding and select backfill around the plastic pipe.
Colo., and knew Johnson’s Tesmec TRS-110 trencher could handily cut through the rock – and do it quicker, less expensively and with less environmental disturbance than blasting. With 25 years’ experience in drilling and blasting pipeline trenches, Johnson read articles about trenching through rock and decided to investigate. The result was purchase of the big 100,000-pound, 365-horsepower Tesmec TRS-110 tracked trencher equipped with a double-wide 34-inch chain and capable of trenching to a depth of 12.5 feet. Among the factors that convinced him to move into the trenching field: The trench can be cut to the exact depth required without damaging the surrounding environment, and the fine spoil produced by the trencher can be used for bedding and backfill, eliminating the need for further crushing or hauling. In Pinewood Springs, the 6.5-foot-deep trench along the north edge of Pima, Wichita and Kiowa roads passed through sections of solid rock, but also sections of essentially rockfree dirt. Fortunately, the existing domestic water line serving homes along the route was north of the path of the new pipeline, and all homes along the route were on the north side, so the only utilities in the way were telephone cables into the residences. Where these lines crossed the trench path, the trencher simply skipped ahead a few feet before resuming its work, and a backhoe or large hydraulic excavator would be called in to laboriously dig through the rock around the phone lines. Through much of the Iowa Road portion of the trenching, the big Tesmec trencher averaged 6.5 feet per minute, and even with the substantial amount of rock on the job, tooth replacement was averaging only one every 50 feet, whereas one every 20 feet is typical in solid rock. acppubs.com
ROCKY MOUNTAIN CONSTRUCTION July 24, 2006 5
Trenching In Rock
Both the large- and small-diameter pipe were pre-fused into continuous lengths suited to the installation, with breaks where phone cables crossed the path. This made actual installation a simple task, using a backhoe/loader to place bedding, lower the pipe into the trench and backďŹ ll over it. The entire project was completed in less than two weeks. Ron Johnson has found great demand for his rock trenching services and has done work in Colorado, Utah and Wyoming. Already in the position of having to turn away jobs his trencher could easily handle if the time was available, he is looking toward acquisition of a second machine in the near future. â–
Above: Cutting a trench 34 inches wide and 6.5 feet deep, the trencher made short work of what would otherwise have required drilling and blasting to excavate a trench through areas of solid rock. Left: Where telephone lines crossed the path of the trench, the trencher skipped forward and a backhoe laboriously cut through the rock around the cables.
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July 24, 2006
ROCKY MOUNTAIN CONSTRUCTION
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