How do open-pit mines differ from underground mines for uranium deposits?

The primary difference between open-pit and underground mining for uranium deposits is determined by the depth and geometry of the ore body.

• Surface/Open-Pit Mining: This method is used for uranium deposits located near the surface. It involves building access roads and stripping away overlying waste material to expose the ore. Because surface mining allows for the use of large earth-moving equipment, it is generally more productive and cost-effective per ton of material moved than underground methods. However, it often requires removing several tons of waste for every ton of ore extracted.123
• Underground Mining: This approach is utilized for deep deposits, typically ranging from 300 to 1,200 meters (1,000 to 4,000 feet) below the surface. Because the cost of removing waste to reach such depths is prohibitive, underground techniques—such as vertical-shaft and drift mining—are employed. While underground mining is more expensive and has lower productivity than open-pit mining, it is more selective, allowing miners to extract primarily ore rather than large amounts of waste. Consequently, underground uranium ore must often be of a higher grade to remain profitable.134