Definition - What does Tailings mean?
Tailings are waste by-products from the mining and extraction of resources. They consist of particles of rock, water and leftover extraction chemicals. In addition, chemical reactions can take place that produce other chemicals that were not previously present in the tailings.
Safeopedia explains Tailings
Tailings present an environmental hazard depending on their nature, and their storage and disposal remains an enormous problem for the mining industry. The EPA regulates the safety of drinking water, and tailings can contaminate water sources if poorly managed, so various regulations related to tailings are in place. When environmental impact assessments are submitted during applications for a new mine to be opened, the way in which tailings are to be managed are an important element, and sites producing tailings are usually subject to strict regulations regarding their disposal.