by KTNA Staff ~ September 29th, 2011
Photos by Laura Wright
By Laura Wright–Another kind of harvesting is going on this autumn besides potatoes and it’s a banner crop. Rock harvesting is booming on some area roads right now. Bills Stearns, who holds the contracts to maintain upper valley roads, says we have no shortage of rocks on the gravel roads up here.
Stearns, owner of D&S Road Services, is using an “In-Place Rock Crusher,” the first in Alaska, on select roads. The machine is quite understated. At only 7-feet 6-inches wide, it looks like an oversized mower being pulled by a tractor. But underneath the cover is a rotating drum with large steel teeth that pulverize the rock as it spins down the road; occasionally spitting rocks out the sides and causing people nearby to cover their ears.
When a road is graded, the larger rocks can get brought up to the surface and then are bladed into the ditch. Look at any gravel road and you’ll see lots of large rocks in the ditch. Operators often pull material out of the ditch to maintain roads, so it is an ongoing process of rocks in and out of the ditches. Stearns wanted to clean up the ditches but scooping the rocks out and hauling them away was far too costly and labor intensive. He was on the search for a solution for ten years before he discovered this moving rock crusher, manufactured in Italy, on the Internet.
The first road to get the treatment was South Birch Creek Boulevard. One mile was completed last week. Stearns said the machine is working beautifully and doing everything that the manufacturer said it would do.
A road grader first pulls material up from a ditch and forms a windrow of gravel and rocks. Next comes a 33,000-pound tractor pulling the 11,000-pound crusher “mowing” the windrow; crushing the rock and leaving a 7-foot wide packed gravel bed. The crusher goes into the roadbed two inches pulverizing the bigger rocks and bringing the fines up to the surface. The machine can “harvest” rocks at a rate of .4 miles per hour
One ditch is done, then the other side, then a third windrow is formed down the middle of the road and crushed. Each time, it is followed by a roller for final compaction. It takes six hours to complete a half a mile of road.
When asked what was the reception by the public, Stearns said that 90% of the phone calls have been positive and the other 10% questioned the cost of the machine. It is $107,000 dollars and that does not include the tractor, which Stearns is renting. The borough has contributed money toward using the crusher but not toward the purchase. Road Service Area 29, Talkeetna and Road Service Area 15, Caswell, both purchased the processing done this fall.
The moving crusher requires only one operator. It takes training to sense how the machine works best. Operators are still getting a feel for the machine and need to learn to balance the power with the speed as well as the load of this PTO driven machine.
Stearns and crew will do two miles of Bendapole Road in Caswell, two miles in Willow and two and a half miles in Big Lake before the snow flies.