2018-08-10_PERMIT FILE - M2017032

Home Browse Search

GEOTECHNICAL STABILITY EXHIBIT (CONT) Page 3 August 10, 2018 in that area will be approximately 4120 and the base of the building is approximately 4155 . The top of the mine face will be approximately 35 feet below and 180 . 5 feet north of the building and the slope will be mined 3h to lv. SECTION F - DITCH SETBACK - SAFETY FACTOR 4 . 9 - Is located in the northeast part of the permit area where the pre-law dirt pile will be removed. The floor of the lake in that area will be approximately 4115 and the top ditch bank is approximately 4135 . The top of the working face will be approximately equal to and 140 feet south of the bank. Reclaimed slope SF = 5 . 8 SECTION G - COUNTY ROAD SETBACK - SAFETY FACTOR 3 . 2 - Is located in the east side of the permit area where mining will be along CR 22 . The floor of the lake in that area will be approxi- mately 4115 and the top of bank is approximately 4135 . The top of the working face will be approximately equal to and 65 feet west of the ROW line . Reclaimed slope SF = 4 . 2 As shown on the Reclamation Plan Maps the slopes outside the current permit have been in place for many years and will not be redisturbed by this mine . For those structures where the working face will be mined and cut/filled we included a safety factor for the cut face and for the final reclamation slope . The material in the mine wall will be in-place sand and gravel and assumed to be cohesionless and having an assumed natural friction angle ((D) of 35' (z1 . 43 : 1) . Using the measured angles from the cross sections, the safety factors for each slope were calculated using the 35o (T) as the base angle . The safety factors are shown in the following table using the formula FS = Tanlb =Tan6, where A is the slope angle from the toe of the created slope to the closest structure . The Safety Factors have been calculated for the '5: 1 and the 3 : 1 slopes at each cross section location and are shown on the at- tached Table B .