APPCOR10053 - Laserfiche WebLink

Home Browse Search

-11- Oneration Plan - Rule 2.05.2 It is unclear from the information presented in the application what the extent of mining will be for the entire Life of mine operation. If the applicant plans, over the life of the mine, to develop other coal seams besides the C-seam, the application must be revised to contain a general description of all operations proposed to be conducted within the other seams. This information should include a description of the type and method of coal mining procedures, engineering techniques, anticipated annual and total coal production, measures to be used to maximize the use and conservation of the coal resource, and an appropriate map delineating each area of land over the life of the operation for which it is anticipated a new, separate 5-year permit will be obtained, according to the anticipated sequence of underground mining. It is unclear from the information presented in the application what the extent of new disturbance will be on the existing portal bench and bench access road. The applicant should indicate for these areas whether any additional cut and/or fill work will be conducted during construction and relocation of the Bear No. 3 surface operations and facilities, and whether the portal bench will be extended in either direction to accomodate the two additional portal entries proposed for the mine. Ponds, Impoundments, and Diversions - Rule 2.05.3(9) Two relatively minor concerns were noted with respect to the sediment control system for the Bear b3 portal and facilities area. 1. Collection Ditches Ditches A and B have design velocities of 7 and 9 feet per second, respectively. Since the majority of materials to be encountered during ditch construction will be tight sandstones, complete ditch lining should not be necessary. Where unconsolidatr_d material is encountered the material should either be removed or protected by rock riprap with a D50 of 6 inches or greater. Two severe curves occur near the culvert A location. At the curved sections of Ditch A above and Ditch B below this culvert, the design depth should be increased by 0.5 feet and rock protection of the outside edge of the ditch must be provided. 2. Sediment Pond The method of design for the emergency spillway is a derivitive of Manning's equation. The depth of flow at the mouth of an3e~pergency spillway is better approximated by a weir equation 4=CLH. /LL Using this equation, with a value of C=3 results in an H of 1.29'. Adding one foot for freeboard requirements results in a total rcqu.ircr7 dr_pth of 2.29'. The applicant must construct the emeryency .spillway of the sediment pond at least 2.2' deep including riprap Lining.