Photo CaptionAerial view of evaporation ponds at the Potash Plant near Moab, Utah. Salts are mined and pumped up from deep below the surface, and the solution is concentrated in these evaporation ponds. “Evaporation Ponds,” photo by Jesse Varner, Flickr. Dye similar to food coloring is used to color potash evaporation ponds. The oil and gas industry spent $100 million.