Tailings are often classified as slurry or sludge. The latter refers to a mixture of fine gangue particles and process-affected water. Tailings sludge can contain dissolved metals that can contaminate the groundwater. Learn more info. check out here: https://www.youtube.com/watch?v=uuY4gc8_v3s https://www.youtube.com/watch?v=uuY4gc8_v3s