Chat (mining)

Historic lead and zinc mining in the Midwestern United States was centered in two major areas: the Tri-State district covering more than 2,500 square miles (6,500 km2) in southwestern Missouri, southeastern Kansas, and northeastern Oklahoma and the Old Lead Belt covering about 110 square miles (280 km2) in southeastern Missouri.

The EPA, the states of Oklahoma, Kansas, and Missouri, local communities, and private companies continue to work together in implementing and monitoring response actions that reduce or remove potential adverse impacts posed by remaining mine wastes contaminated with lead, zinc, cadmium, and other metals.

Dry processes produced a fine gravel waste commonly called "chat."

The wet processes resulted in the creation of tailing ponds used to dispose of waste material after ore separation.

Milling produces large chat waste piles and flat areas with tailings deposited in impoundments.

This image, taken in 2010, shows a chat pile near Picher, Oklahoma . These piles contain lead-contaminated dust and are part of the reasons the area is designated as the Tar Creek Superfund site .
Another image, taken in 2006, of chat in the Tar Creek Superfund site .