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Crusher gives new life to old concrete

Thick slabs of concrete are hoisted gently into the mouth of the jaw crusher.

Sun Advocate Reporter

Just in time for Christmas, the county's road department got a present - a 54-ton, $360,000 jaw crusher that can pulverize concrete slabs into pebbles.

While the crusher is painted red, its true color is "green," meaning it's a massive recycler of what used to be junk concrete. Those cement chips make good road base, according to County Commissioner Bill Krompel. Given the fact that the county has about 550 miles of unpaved road to maintain - including the Nine Mile Canyon Road - the demand for the product is there, he noted.

The crusher is mobile, able to crawl forward on treads like a tank. If a paved road is being torn up, it can follow behind a demolition team, swallow and chew the big chunks of concrete they feed it, and leave behind a new layer of chips for base.

At a demonstration for county and civic officials Thursday, road workers put the machine through the paces at the county gravel pit near Dugout Canyon. A backhoe hoisted slabs of broken concrete one at a time into the hopper. Once inside, big jaws crushed the concrete, almost the way molar teeth crunch potato chips.

There is a powerful electromagnet inside the machine that attracts steel and removes rods of rebar from reinforced concrete. Every few seconds, a mangled rod would be spit out the side of the machine.

The crushed output was screened to regulate the size of the output. Bigger, fist-sized chunks rode on a conveyor assembly to one pile. The smaller, 1 1/4 inch bits were conveyed on another belt to their own pile.

Depending on the size and toughness of the feed material, the crusher can chew up and spit out anywhere from 200 to 400 tons per hour.

This is not a plug-and-play piece of hardware. The federal Mine Safety and Health

Administration requires 40 hours of training for anyone working with the machine, with 16 hours of refresher courses later. Visitors are required to attend a 15-minute training before being allowed on site, and have to stand well away from the crusher while it is running.

Hard hats are mandatory for all.

Helper City Councilman Gary Harwood, who attended the demonstration, said the machine would enable his town to get rid of the concrete slabs it has had pile up after road construction and repair.

The crusher will also ease some pressure on the county landfill. Concrete now joins tires, batteries and metal items on the list of things that will be recycled rather than buried.

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