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• Mean Wind Speed - 2.0 m/s (default value for program) <br />The resultant dose to the nearest residence in this scenario was 0.2 mrem/yr, which is <br />well below the regulatory limit of 10 mrem/yr. <br />4.3.2 Phase I Emissions <br />The prorated exposed ore area of the Whirlwind Mine at the end of Phase I is <br />approximately 116,000 square feet giving a total radon-222 emission of 20.8 Ci per year. <br />This value, along with the following inputs, were entered into the COMPLY-R program. <br />• Release Height - 0 (ground level from portal) <br />• Distance from Source to Nearest Receptor - 835 meters (from Whirlwind portal <br />to Zabronsky Parcel residence location) <br />• Mean Wind Speed - 2.0 m/s (default value for program) <br />The resultant dose to the nearest residence in this scenario was 1.2 mrem/yr. <br />4.3.3 Phase II Emissions <br />Dose estimation for Phase II of the Whirlwind Mine development was split into two <br />parts, Phase IIA and Phase IIB, to account for two distinct scenarios. Phase IIA considers <br />that all of the ventilated air and radon-222 emissions exhaust through the Packrat portal. <br />This would be the case if the drift from the Whirlwind Mine to the Packrat Mine were <br />completed prior to construction of exhaust shaft C L It is likely that the completion of the <br />Packrat drift will precede the completion of Shaft Cl because establishing a secondary <br />escape-way is a high priority. It is also the more conservative of the two situations <br />because of the closer proximity of the Packrat portal to the nearest resident and the design <br />of the exhaust (i.e. no vertical momentum of exhaust at the Packrat portal) results in a <br />higher estimated dose. Phase IIB considers that ventilated air and radon-222 emissions <br />are split equally between the Packrat portal and exhaust shaft C l. The prorated exposed <br />ore area of the Whirlwind Mine at the end of Phase II is approximately 212,000 square <br />feet giving a total radon-222 emission of 38.2 Ci per year. This value, along with the <br />following inputs, were entered into the COMPLY-R program. <br />• PR Portal Release Height - 0 (ground level) <br />• Exhaust Shaft C 1 Release Height - 2.0 meters (6 feet) <br />• Exhaust Shaft C1 Vent Diameter - 2.5 meters (8 feet) <br />• Distance from Packrat portal to Nearest Receptor - 805 meters <br />• Distance from Exhaust Shaft Cl to Nearest Receptor - 1,416 meters <br />15