Operations

The Piñon Ridge Mill will initially be built with a capacity of 500 tons of uranium ore per day for a projected life of 40 years. The ultimate design will accommodate a capacity of 1,000 tons per day. The Piñon Ridge Mill is being completed by a variety of highly qualified contractors based on a proven track record in designing and building similar facilities. These contractors are also helping Energy Fuels prepare operational and monitoring procedures that are protective of human health and the environment.

What does a Mill do?

In a conventional uranium mill, the first step is to crush the ore to allow the process chemicals to remove the uranium from the host rock. Then the uranium goes through a purification process and is precipitated, dried, and packaged in 55-gallon drums for shipment off site. The final product is called yellowcake because it typically is a yellow solid that looks like baking flour. Chemically yellowcake is U3O8 with a varying number of water atoms attached.

At the Piñon Ridge Mill, the radioactivity associated with handling and processing uranium requires some special management. As noted, Colorado requirements are patterned on the programs and procedures developed by the NRC. Please refer to the following websites for an explanation of radioactivity and the controls that are required for uranium mills.

NRC Information:    http://www.nrc.gov/about-nrc/radiation.html

Colorado Information: http://www.cdphe.state.co.us/hm/rad/radrelated.htm

Numerous safety systems will be present in the Piñon Ridge Mill to protect workers from being exposed to excess levels of radiation. Area air monitors will be located throughout the Piñon Ridge Mill to monitor the concentrations of uranium dust in the mill. Workers involved in potentially dusty operations will wear breathing-zone air monitors to monitor the air that they breathe. For those workers exposed to higher concentrations of uranium dust, urine samples will be collected and analyzed to determine the total uranium that has been inhaled and ingested. In addition those workers exposed to the highest levels of gamma radiation will wear gamma-monitoring badges, similar to what x-ray technicians and airline screeners wear. Other protections include regular power washing of equipment and vehicles, monitoring of the amount of time a worker is exposed to radiation, and general housekeeping and personal hygiene.

Tailings and Radon:

Solid waste products from the uranium milling operation are called “tailings” – or what is left at the “tail end” of the milling process. Tailings consist of everything in the uranium ore except the extracted uranium. The main radioactive materials in the tailings are Thorium-230 and Radium-226 both of which will remain in the tailings for long periods of time due to their long half-lives. After the uranium ore is processed in the mill, the tailings are pumped in a slurry to the tailing cell, consisting of a synthetically-lined earthen impoundment. After a tailings cell is full, the entire cell is covered with earthen materials in accordance with detailed engineering criteria to form a “cap” on the tailings and the radon gas.

Radon gas is released from the tailings and disperses into the air. Since radon from the tailings is not contained during mill operations, it is a potential source of radiation to someone who might live immediately adjacent to the mill (defined as “the closest downwind resident”). Therefore, radon concentrations are both monitored and modeled to assure that the resulting radiation doses would not cause any harm to someone living on the mill’s property line. For other residents living further away from the tailings (the closest actual residents are three-to-four miles away), the radon does not present a hazard due to its dilution in air.

To limit the amount of time any one cell is in operation, the Piñon Ridge Mill is being designed to use multiple cells that will be utilized sequentially. Each cell is designed to hold approximately 2.3 million tons of tailings. Each cell is designed with a multi-layered lining system to contain all tailings solids and liquids. The liner system is designed to prevent a migration of wastes out of the tailings cells during the life of the Piñon Ridge Mill and post-closure period.

To continuously monitor the liner system, a leak detection system will be installed and operated. Measured parameters will be monitored by Energy Fuels personnel and reviewed by CDPHE personnel.