The basic objective of this project was to determine the cost- effectiveness of dust controls used on unpaved mine haul roads. Field testing was conducted at three surface coal mines (two in Wyoming, one in southern Illinois) for a total of 20 weeks. The highest control efficiency measured for a chemical dust suppressant, 82 pct, was for calcium chloride 2 weeks after application. Generally, however, the control efficiencies hovered in the 40 to 60 pct range over the first 2 weeks after application, and then decreased with time. After the fifth week, the limited number of data points suggests a control efficiency of less than 20 pct. Composite watering data were fairly uniform. Watering once per hour resulted in a total suspended particulate control efficiency of approximately 40 pct. Doubling that application rate increased the control effectiveness by about 15 pct to 55 pct. Chemical dust suppressants (primarily salts and lignons) can be shown to be more cost-effective than watering under some conditions. Data summaries and the analysis of data are contained in Volume I. Volume II contains basic data.