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The ventilation plan for the Whirlwind Mine in Phase II is a simple "Y" shaped circuit. <br />The Whirlwind portal (Al) serves as the fresh air intake. Fresh air is drawn down the <br />decline to a point where it splits between the two branches leading to the ore zones. The <br />northern branch leads to the "A" ore zone. Fresh air is drawn into the front end of the <br />stopes and is exhausted from the back end of the stopes into the Packrat Mine. In this <br />branch, contaminated air is exhausted to the atmosphere through the Packrat portal (A2) <br />by an exhaust fan mounted in a bulkhead near the portal. The exhaust fan at the Packrat <br />portal will move approximately 100,000 cfm of air. <br />The second branch of the "Y" circuit leads to the "B" ore zone. Fresh air from the <br />Whirlwind decline is drawn into the front end of the stopes and is exhausted from the <br />back end of the stopes into an exhaust shaft (CI). Contaminated air from the "B" ore <br />zone is exhausted to the atmosphere through this shaft by an exhaust fan mounted in a <br />bulkhead at the base of the shaft or at the top of the shaft. <br />The exhaust fan at the "B" zone exhaust shaft (C 1) will also move approximately <br />100,000 cfm of air. The "B" ore zone exhaust shaft is to be 5 to 8 feet in diameter and <br />lined for its full length. Total mine ventilation intake at the Whirlwind portal will be <br />200,000 cfm. <br />To control radon-222 influx from the historically mined areas of the Packrat Mine, <br />temporary brattice curtains will initially be installed in a progressive fashion along the <br />length of the main Packrat ventilation drift as the new ventilation system is established. <br />The brattice curtains will then be replaced with permanent bulkheads in the same <br />progressive fashion (i.e., working from the inside out with fresh air from the Whirlwind <br />portal being directed to the work area). Ventilation pressure will be controlled between <br />the two branches by the use of regulators and air-doors, if necessary. The existing 10- <br />Straight shaft in the Packrat Mine will be sealed or regulated to function as an additional <br />air intake. Because of its size (32-inch diameter), it is too small for effective use in the <br />primary ventilation circuit. Booster fans, vent bag, and brattice curtains will be utilized <br />to direct air into individual work areas. <br />3.3.3 Phase III Ventilation System <br />Phase III of the ventilation plan, shown on Figure 7, is an expansion of the Phase II plan. <br />Phase III includes development of the ore-bodies identified to date and the addition of up <br />to six more ventilation shafts. These shafts will serve as intake air locations for the <br />newly developed stopes. <br />9