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<br />ALLEN MINE <br />TECHNICAL REVISION N0. 1 <br />The purpose of this revision is to allow construction of a <br />conduit/spillway structure to divert undisturbed drainage away <br />from the slide area near the coal silos. Construction of this <br />conduit/spillway system will prevent the slide area from <br />becoming supersaturated and should aid in the prevention of <br />further slides in this area. <br />CFI desires to commence construction in early April of <br />this year and anticipates that the project will take three to <br />four weeks to complete. The location of the proposed <br />construction is shown on the location map (Exhibit A) and is <br />within the permit boundary. <br />Construction of this project will entail building an inlet <br />structure and outlet structure connected by 130 feet of an open <br />trapezoidal flume. The elevation difference between the inlet <br />and outlet is approximately 50 feet. The inlet structure is <br />• planned to be of substantial concrete and metal construction. <br />The inlet structure has been designed to feed water to the <br />trapezoidal flume at the rapid rates required. Drawings of the <br />inlet structure are included in Exhibit B. The outlet <br />structure is also to be of concrete and metal construction and <br />especially designed to change the direction of the water flow <br />and to dissipate the erosive power of the water. Drawings of <br />the outlet structure are included in Exhibit B. The outlet <br />structure is also to be of concrete and metal construction and <br />especially designed to change the direction of the water flow <br />and to dissipate the erosive power of the water. Drawings of <br />the outlet structure are included in Exhibit B. <br />The upper section of the flume is 40 ft long and is at an <br />angle of 17 degrees. The lower section of the flume is 91~ <br />long and is at an angle of 39-1/2 degrees. The two sections <br />are connected by a concrete junction box. A drawing of the <br />junction box is also included in Exhibit B. <br />This conduit/spillway system has been designed to safely <br />pass the flow generated by a 10-year 24-hour storm event. The <br />flow calculations are included in appendix A. <br />After completion of the structure, the area will be graded <br />similar to its previous condition and the area will be <br />• revegetated in accordance with the applicable sections of <br />Permit Application No. C-012-81. <br />3 <br />