2012-10-29_PERMIT FILE - P2011012

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Each well would be drilled to approximately 5,500 feet using water -based mud. Any water -based mud cuttings from the drilling operation would be stored and allowed to dry on a temporary lined and bermed pad and later sampled and tested. If potential contaminants are below maximum allowable concentrations and levels, the material would be buried on location. A typical well would have conductor casing set at approximately 40 feet, surface casing set at about 1,500 feet, and intermediate casing set at roughly 5,500 feet. After setting the intermediate casing with cement and reaching the applicable depth, the mud would be changed from water based to an oil based mud system. The used water -based mud would be removed from the storage tanks and transported offsite to either the next drilling location for reuse or to a permitted commercial waste facility for disposal. The mud tanks would be washed out and filled with oil -based mud made with diesel and calcium chloride (CaC1) solutions in the premix tanks. Coring operations would be conducted using the oil -based mud system. Any solid cuttings drilled with oil -based mud would be put in steel containers and transported to a permitted commercial waste disposal facility. The oil -based mud would be entirely contained within tanks and the wellbore. When coring operations are complete, the oil - based mud would be transported offsite for reuse, recycling, or disposal at a permitted commercial waste facility. After completion of all drilling operations, the water -based drill cuttings would be allowed to dry on the temporary pad and then sampled and tested to determine whether onsite or offsite disposal is required. All water -based and oil -based muds would ultimately be disposed of or recycled at a licensed commercial waste facility. See also Section 2.2.8 on Hazardous Materials. The flare pad would contain a burner used for disposal of hydrocarbons during clean -up, emergency shut downs, and for disposal of small volume waste streams of mixed gasses that cannot easily or safely be separated or stored on location. The flare pad would be an area 15 by 35 feet in size surrounded by a 3 foot high berm (Figure 3). Drill Holes Each wellbore would be drilled in three sections: an upper 10 -inch diameter rotary drilled section, an intermediate 8 -inch diameter rotary drilled section, and a lower 6 -inch diameter core drilled section (Figure 4). The upper 10 -inch diameter hole would be drilled to about 1,000 to 1,500 feet below ground surface (bgs), and a 9 5/8 -inch surface casing string would be set at least 50 feet into the Chinle Formation. The hole would be lined with steel casing and cemented all the way back to ground surface. Next, an 8 -inch diameter hole section would be rotary drilled to approximately 5,500 feet bgs and lined with temporary steel 7 -inch casing. This intermediate casing string would be cemented at the base to roughly 150 feet above the intermediate casing shoe. From 5,500 to 6,000 feet bgs a 6 -inch diameter core hole would be drilled into the Paradox formation. Oil - based mud would be used in the deepest part of the wellbore to prevent dissolution of RM Potash Exploration Project 20 Environmental Assessment