Calcium chloride plays, perhaps, its most important role in mining applications as a maintenance material for haul roads. And it does it all by controlling dust. Here’s how.
As calcium chloride absorbs moisture from the air, it keeps haul roads damp, even on the hot, dry days. It actually becomes a thin liquid coating on each particle of dust, dirt and gravel. As a result, dust particles (called fines) remain in place. You eliminate the problems of slowdowns caused by clouds of dust reducing visibility for drivers. You reduce the chance of equipment failures from dust clogging bearings, seals and other components. And you meet clean air standards for working environments.
Although most states do not have a law regulating “fugitive dust emissions” from surface mines, many of them will in the future. Some states currently set particulate emissions standards and maintain monitors on the mine perimeter to assure compliance. The State’s Environmental Quality Department of the Environmental Protection Agency (EPA) could, in the future, shut a mine down for violating state or federal particulate emission standards, such as the National Ambient Air Quality Standard for Particulates (NAAQS). If not shut down, they could be required to apply “reasonable available control technology” (RACT). Calcium chloride would fit in this RACT niche.
This is all accomplished with far fewer “watering” runs, too. In one case, a company that had been watering all day, every day got better dust control with just one watering application per week after an initial treatment with calcium chloride. Savings were estimated at $228,000 per year.