News Delta County

From mountains to molehills: County’s used tires are recycled

Published January 17, 2007

By Hank Lohmeyer
Staff Writer

In a notable reversal from the usual course of things in life, mountains are being turned into molehills at Delta County’s Adobe Buttes Landfill

Turning a mountain of used tires into little piles of steaming shredded rubber is a big job. It takes a big machine.

An impressive piece of equipment that was up to the task started work at the landfill last week turning Delta County’s mountain of used tires into shredded rubber which, for current lack of a better use, will be used as cover material for the landfill’s daily operations.

The county participates in a multi-county consortium that currently includes 13 Colorado counties, explained Bruce Bertram, Delta County solid waste coordinator. The participating counties all pay a share of the cost for the tire grinding behemoth, sometimes called a tub grinder because of the giant tub into which the tires are placed for shredding.

The machine’s real name is the HogZilla and it is manufactured by the C.W. Mill Equipment company of Sabetha, Kan.

It makes a circuit around a Colorado county dump grand tour, stopping at each location for as long as it takes to digest the problem at hand, and then moves on to the next stop.

The machine was scheduled to stay at Adobe Buttes “for as long as it takes,” to complete the work there, Bertram said.

The county has paid $10,000 for its share of the mechanical tire munching machine’s work, and the project is also funded by grant money from the state.

The HogZilla and its operator arrived on site at Adobe Buttes last week and set to work churning and chomping a mountain of used local tires that Bertram “guesstimates” at maybe 60,000.

The operator’s climate controlled cab is a showplace of creature comforts. From his perch above the rotating tub that feeds tons of tires to the whirling shredding blades in the bottom of the bin, there is air conditioning, stereo, a cushy seat, and plenty of room to store munchies.

County road department employees took a moment to stop by and admire the massive machine at work during its second day on the job last Thursday.

Operating the mechanical grapple with two armchair-mounted hydraulic controls, the operator simply grabs a claw full of the tuckered-out treads and drops them into the tub.

The tub’s rotating motion keeps the contents stirred up and moving constantly across a heavy steel grate located at the bottom of the tub.

The shredding blade assembly, truly an impressive piece of machinery, contains several banks of cutting blades. The assembly and its cutters, spinning at many hundreds of revolutions per minute, catches pieces and parts of told tires as they move across the grate.

Then the one-thousand horsepower of Caterpillar twin-turbo V-12 power that drives the cutting blades assembly makes short work of rubber at hand.

Massive heat generated by the shredding operation sends plumes of acrid smoke into the air and shrouds the operation with the smell of burning rubber.

Sometimes the rubber does catch fire. A water truck is kept nearby for such events, and it also provides a continuous stream of cooling, lubricating water into the tub during the grinding operation.

Finally, the shards of rubber drop onto a conveyor belt and transported in a neat pile for use in the landfill operation.

There is plenty of dirt at the landfill for use as cover. But something has to be done with the old tires.

Most of the tires at the landfill are steel belted radial passenger and light truck tires. The presence of stringy remnants from the shredded steel belts in with the chunked-up rubber makes the whole mish-mash of steel and rubber unsuitable for anything but landfill cover.

Bertram says that if the shredding operation were able to devise a way of removing the steel from the rubber that the clean, reclaimed rubber from the tires would be a product with considerable economic value.

The county accepts unmounted tires from residents at the landfill for no charge. The tires cannot be mounted on rims and there may be certain size restrictions too.

Tire shops are charged a fee for disposing of their tire carcasses at the landfill, and that fee helps pay the cost of the county’s participation in the circuit-riding tub grinder.