Mine tailings may find use in asphalt

Thursday, August 1st 2002, 12:00 am
By: News On 6

TULSA, Okla. (AP) _ A two-year study at the University of Oklahoma may determine whether waste from abandoned mines in northeast Oklahoma can safely be used in highway asphalt.

The Oklahoma Department of Environmental Quality signed a contract with OU on Monday to test how much raw chat can safely be used in highways.

The goal of the $200,000 study is to increase the safe use of the lead-contaminated material. OU also will perform simulated weathering and milling to study the long-term safety of chat in asphalt.

Chat is a mining waste that contains metal contaminants such as lead, zinc and cadmium.

The Tar Creek Superfund Site in northern Ottawa County is riddled with piles of chat that are left over from decades of lead and zinc ore mining and processing. An estimated 75 tons of the residue remain and contain high levels of lead and other metals.

``If we can determine that raw chat can safely be used in asphalt even over time as it weathers and is reworked, then we will greatly increase the rate of chat use,'' said Scott Thompson, director of the DEQ's land protection division.

``This would be a win-win approach to an environmental problem where there are both economic and environmental benefits,'' he said.

Getting rid of the chat piles in the Superfund site has been one of the goals of the U.S. Environmental Protection Agency. Binding the chat into a durable product, like concrete or asphalt, is one of the few measures the EPA has approved.

The chat-in-asphalt mix used in the OU study must meet Oklahoma Department of Transportation specifications for highways and interstates.

Simultaneously, the state Transportation Department and Oklahoma State University are evaluating the use of chat as a base material in state and interstate highway construction.

``In two years, we will have answers about the long-term safety of chat in asphalt and will be in a great position to expedite the safe and economic use of chat,'' said DEQ Executive Director Steve Thompson.

The agreement marks the second contract that uses part of the $4 million in funding from the state Legislature for the Tar Creek area.

A contract was signed in June with the Oklahoma Conservation Commission to remediate land that has been affected by mining waste.

In addition, the EPA has begun removing lead-contaminated soil from school yards in Picher and Miami, Okla., and will continue residential yard remediation in October.