According to the Associated Press, certain gravel roads in western North Dakota use erionite, a mineral that is mined in the Killdeer mountains. Erionite forms wool-like fribrous masses among rock formations and has properties similar to asbestos. Scientists suspect that, like asbestos, erionite collects in the lungs in those fibrous masses, a factor that could lead to lung cancer in people who have long-term exposure to it.
The usual line from a preacher at a burial is "Ashes to ashes, dust to dust". Well something along those lines may soon be happening to some roads in Michigan. After my recent treatise on the process for (de)constructing roads in the Great Lakes state, an article turned up in the Lansing State Journal indicating that some county officials are contemplating an alternative to repaving decaying thoroughfares. With a complete repaving costing $100,000 per mile and repeated patching potentially costi