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M. - <br />There is no indication that any acid-forming or toxic forming materials will be encountered <br />on site. Please refer to Section 2.04.6. Please refer to Section 2.05.3(8) for a discussion of <br />the applicant's method to handle debris and non -coal waste. <br />If sustained combustion of debris or non -coal waste becomes a problem the applicant will <br />be prepared to react appropriately. Chemical fire extinguishers will be available in the <br />shop warehouse area and on mobile equipment. A water truck will be available to respond <br />to any problem area. Earth moving equipment may be available to smother a fire if <br />necessary. <br />(2)(g) Sealing and Managing Mine Openings <br />Sealing of the openings which access the underground coal mining operations at the <br />New Elk Mine will be completed upon the final closure of the operation. Sealing will <br />consist of installation of bulkheads near the surface of the openings to prevent entry and <br />collapse of the surface. Bulkheads will consist of a minimum of an 8 inch thick block seal <br />as shown on Figure 15 -Typical Mine Opening Seal. Particular care will be taken to ensure <br />that excessive pressures do not collect on the inside of the seal and cause seepage or <br />erosion around the seal. In addition, the seal will be sufficiently strong to support the <br />surface material placed over the opening. <br />Air shafts that have been constructed at the New Elk Mine are cement lined to maintain the <br />integrity of the shaft and prevent contamination of intercepted aquifers. Upon final <br />abandonment, these shafts will be sealed with a steel reinforced cement cap. The steel form <br />will be constructed adjacent to the shaft and set into place using a crane or other mobile <br />equipment. The cement cap will then be poured in the form to complete the seal. Figure 16 <br />Airshaft Seal, shows a typical air shaft seal which will be utilized by the Operator. <br />All boreholes, wells, and exploration holes will be plugged or otherwise sealed to <br />prevent contamination of groundwater intersected by the hole itself. Surface plugs <br />and backfilling of the holes will be completed to minimize safety hazards to man and <br />wildlife in these areas. Figure 16A -Typical Borehole Seal, shows a typical borehole seal <br />which will be utilized by the Operator. <br />A probable roof failure in the West Portal Mains approximately 500 feet inby the sealed <br />manway opening resulted in a sink hole migrating to the surface. Repeated attempts to <br />backfill the area failed due to piping of surface waters into the mine. The Operator <br />permanently sealed this potential mine opening by excavating down to competent strata <br />surrounding the failure zone (approximated at 3-5 foot in diameter). The zone of failure <br />was backfilled to the approximate level of the competent strata. A wire -mesh reinforced <br />concrete plug at leased twice the diameter of the failure zone was poured in place across <br />the area. A six inch layer of bentonite was placed over the concrete plug to provide a <br />hydrologic seal at the contact between the concrete plug and the surrounding strata. The <br />excavation was then backfilled to the natural surface. <br />Section 2.05 RN -6 10/17/2016 <br />