2011-06-06_PERMIT FILE - M2011015 (3)

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spacing to minimize ground vibration, loading densities and shot patterns on file for each event, seismic recordings(minimum 2 per shot) showing peak velocity of ground vibration and air blast levels for each shot. This Blast Monitoring Report will be attached to annual report to RMS as condition of permit. d) Please find attached letter from Rod Schuch, blasting specialist with Buckley Powder, a major supplier of explosives and blasting control technical support for the Rocky Mountain region. Mr. Schuch has reviewed the site parameters and has commented on the typical ground vibration level to be expected at this site. 9. Mine bench surface average slope measure will be 1% or less with exposed bench faces as near vertical as possible for efficient blasting. Mining face length may total up to 800' at maximum pit development including working face and limbs of pit wall development. Access to top of mining bench elevation will be restricted by fence, berm, rock placement or combination to keep unauthorized personnel from vertical mining faces. 10. Specifications and Design of Sediment Control Berm. The Sediment Control berm will be constructed with local soil from as close a proximity to the site as possible. Any disturbance due to soil movement will be re-graded and re-vegetated at the completion of structure. Soil material found along the drainage way has ample fines content for adequate compaction via repeated blade passes with bulldozer or motor grader. The intent of the sediment berm is not so much to impound water as to slow down surface flow velocities in the area where the haul road runs along lower portion of the drainage channel in the southwest comer of the site. A shallow basin no deeper than 18" will be left behind a broad spillway no less than ten feet each side the channel centerline and no less than seven feet spillway width which will be armored using Pyramat, an erosion control product commonly used for storm channel applications. In this case, the product will be used for creating a shallow spillway effect that will allow storm flow velocities to slow and deposit sediment in the shallow basin behind the berm face. The pyramat product is a poly-woven fabric app. I" thick with small cells woven into the fabric. The material is installed using steel pins and anchor trenching techniques over soil smoothed via raking and removal of any rocks at the surface. Once the pyramat is in place, seed is distributed over the pyramat followed by one-half inch of soil to cover the fabric. The pyramat system offers both a substantial physical armoring (50 year UV resistance) as well as promoting the establishment of grasses over the fabric with root penetration through the fabric and into the soils directly below. This system will stabilize the storm channel against erosion of the berm due to intense storm events. If channel stabilization efforts are not successful in establishing and maintaining a grass cover over the bottom and sides as well as the spillway zone, rhyolite rock up to six inches in diameter will be placed in the flow path to slow surface flow velocity during an intense or prolonged precipitation event. Due to the shallow nature of the structure, there will be very little water collected behind the berm and what small amount may be found in the basin after a storm event will percolate into the ground within twenty-four hours. The structure is intended to slow surface run-off during intense weather events and retain sediment that may