Figure 26. Photograph of a coal bed "face" in an underground coal mine showing personnel collecting a channel sample of fresh coal. The collecting team is standing on a floor that has been excavated below the base of the coal bed to facilitate mining. The white color in the background is limestone dust sprayed on the coal face to control coal dust. The coal sample is collected on a clean plastic sheet to minimize contamination from the floor of the mine. This sample is from the Lower Freeport coal bed, Indiana County, Pa., where the bed is about 56 in thick. Photograph by R.W. Stanton (U.S. Geological Survey).