Aerial view of track patterns in an evaporation pond at a potash mine in Moab, Utah, USA. Potash is an impure salt that contains potassium chloride and is used as a fertiliser to improve crop growth and quality. The solution mining method is used to extract potash by pumping water underground to reach the potash ore. The brine is then pumped from underground to the surface, where it is collected in large ponds. Over time, the water from the brine evaporates, allowing the salt to crystallise. To speed up the process, the water is dyed blue, as darker water absorbs more sunlight and heat. Machines scrape the potash crystals from the ponds leaving track patterns behind.