Multimedia Reporting (Kuhr-Musser)

Douglas County will continue to use lightweight mineral fragments for road repairs this year despite a significant rise in the cost of this material.

The county switched to using lightweight shale fragments instead of heavier limestone rocks for sealant about eight years ago. It never looked back on that decision until Monday, when a 31.7 percent increase in the price of the lightweight fragments forced the commission to consider reverting back to the cheaper limestone alternative.

Escalated gas prices caused the sharp increase in lightweight fragment costs. The fragments are manufactured using natural gas and must be transported from Marquette, Kans., and New Market, Mo., which requires even more gas, Doug Stephens, chief of inspections for Douglas County Public Works said.

“It’s a cost you have to pass along,” Ron Vance, sales manager at Vance Bros. Inc., said. His company supplies asphalt to the county.

Limestone rocks, which the commission discussed using as a more affordable alternative, cost half as much as the lightweight shale minerals because they are mined in Douglas County rather than manufactured elsewhere. Stephens estimated the difference in price totals for one year's worth of road repair is about $9,800. Limestone is far more cost efficient, but it cannot compare to the lightweight material’s durability and use.

“There’s a world of difference between the two rocks,” Stephens said. “The limestone works fine, but the other is just better.”

The most important difference between limestone fragments and lightweight fragments is degree of safety. Lightweight fragments create much safer roads. They are approximately half the weight of limestone, according to Keith Browning, county engineer. This is significant because the fragments blow off the road. They aren’t picked up and carried by the wind like limestone rocks, which have caused damage to windshields before. Lightweight fragments are darker and create a more visible contrast with road markings. As they wear, it causes the road surface to become porous. Voids open in the asphalt which allows friction to remain high. Limestone fragments produce the opposite effect over time: street surfaces become polished, making the surface slippery and less skid-resistant. Limestone is also problematic because it produces a significant amount of dust when it is being put down on the road. Several accidents occurred during street sweeping operations when limestone was used in the past.

One drawback for using the lightweight material is that the county might be forced to cut back on repairs in the future if high prices persist. The county has reserved $483,000 of budget money for road sealing in 2006. Using the lightweight shale minerals, which cost $13,810 per mile, it will be able to seal about 35 miles of road. That is eight miles less than the limestone rock, priced at $11,293, would allow for. But County Commissioner Bob Johnson does not anticipate the shortcoming will be a problem this year. He said there is probably enough money in the budget to do what the county has planned. If prices are this high next year, the commission will need to allocate more money for road maintenance. The road segments and total mileage that will be sealed this year will be determined later in the spring.

Ultimately, Johnson said the committee voted in favor of the lightweight material because it performs better and it is safer. Also, he said the county prefers it.

Lawrence resident Amanda Harlan approves of the committee’s decision to use the safer material rather than the cheaper one. Baldwin resident Channette Kirby agrees.

“Safety is definitely more important,” she said.