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MSHA regulations prohibit personnel from going deeper into the mine before ventilation <br />is established. Based on mining experience, Energy Fuels anticipates that the average <br />radon-222 levels in the Packrat Mine will be about 50 to 80 working levels. <br />The total radon-222 in the Packrat Mine was calculated to be 5.11 Ci based on the entire <br />area of the Packrat Mine workings (1,025,800 SF), an average height of 11 feet, and an <br />average radon-222 concentration of 80 working levels, equivalent to 16,000 pCi/L. This <br />is a one-time emission source because temporary and then permanent seals will be used <br />to isolate the Packrat ventilation drift from the remainder of the historic workings as the <br />ventilation system is advanced. The additional dose to the nearest member of the public <br />was input into the COMPLY-R program with the following parameters. <br />• Release Height - 0 (ground level from Packrat portal) <br />• Distance to Nearest Receptor - 805 meters <br />• Mean Wind Speed - 2.0 m/s (default value for program) <br />The resultant dose to the nearest residence was 0.3 mrem. This dose would be in addition <br />to the normal operating dose for the first year of ventilation of the Packrat Mine (Phase <br />IIA). The resulting cumulative dose of 2.6 mrem/yr is estimated for the first year of <br />operation to account for the radon-222 in the Packrat Mine. The program output is <br />presented in Appendix B. <br />17