Jump to main content.

Mining Wells (Class III)

This page describes Class III wells and their uses.  It also describes the various types of Class III wells, explains how their use helps protect drinking water resources, and presents the UIC Program’s requirements that ensure the protection of underground sources of drinking water (USDWs).

Class III Wells
Class III Injection Wells image

Class III Wells - Minimize environmental impacts from solution mining operations.
Visit the Class III Wells page to read more about these wells.

What is a Class III well?
Class III wells inject fluids to dissolve and extract minerals such as uranium, salt, copper, and sulfur. More than 50 percent of the salt and 80 percent of the uranium extraction in the United States involves the use of Class III injection wells. There are about 165 mining sites with approximately 18,500 Class III wells in operation across the nation.

What are the types of Class III wells?
Class III wells are used to mine uranium, salt, copper, and sulfur.

Uranium in-situ leaching (ISL) is the most common method by which uranium is extracted in the United States. A typical uranium mining operation requires injection, extraction, and monitoring wells. The process includes the following steps:
Injection wells are drilled into the formation containing the uranium.

The majority of Class III wells in the United States are uranium ISL wells.

Salt solution mining wells inject clean water to dissolve the salt and the resulting brine (salt water) is pumped to the surface where the salt is extracted. Two methods are used:

If the salt is contained in a dome, a single well typically is used. If the salt is contained in multiple, bedded layers, multiple injection wells are used. Salt solution mining wells make up 5 percent of the Class III wells.

Production wells, which bring mining fluids to the surface, are not regulated under the UIC Program.

Top of page

How do Class III wells protect drinking water resources?
Extraction of metals and salt is necessary to support industrial and economic activities. Solution mining through injection wells is an option that can minimize environmental damage from mining processes.  To prevent contamination of ground water (which in many cases is a USDW) by Class III wells, more fluid is extracted than is injected in solution mining processes, thus preventing fluids from moving out of the mining areas.

Top of page

What are the requirements for Class III wells?
All Class III wells are operated under individual or area permits. Contamination from mining wells is prevented by implementing requirements for mining well operators:

Top of page

Additional Information

Top of page

Safewater Home | About Our Office | Publications | Questions and Answers | Links | Office of Water | En Español

Local Navigation

Jump to main content.