Laserfiche WebLink
Bob Oswald <br />Re: West Sunday Mine, Permit M-1981-021 <br />Request for Technical Revision <br />Page 4 of 5 <br />All vent shafts have a concrete collar approximately 16 feet in diameter and 30 inches thick <br />extending around the bored shaft. The opening of each vent shaft is a hole in the concrete <br />"donut" forming the collar. The vent shaft hole in the slabs is one to two feet larger in <br />diameter than the vent shaft itself. The approximate volume of concrete in each slab is 14 yd3. <br />Reclamation of the vent holes will include removal of the fan and any surface hardware <br />followed by backfilling the shaft with native waste rock obtained from local borrow areas (no <br />dumps exist on the surface at the vent sites as the shafts were upreamed and the cuttings were <br />collected in the mines). The shafts will be filled to within a few feet of the surface (leaving <br />adequate room to dispose of the broken collar) and observed for not less than five days to <br />ensure that no settling of the fill takes place, after which, the top of the hole will be filled with <br />native rock and soil. <br />Dump Grading: Outslopes of dumps will be graded to a slope of no steeper than 2 <br />Horizontal : 1 Vertical to provide a suitable face for reclamation and to blend the reclaimed <br />dump into existing site contours. The general practice will be to reduce all "created slopes" to <br />a gradient of not more than 2:1. However, as a practical consideration there will be occasions <br />when reduction of slopes will not be performed if the required grading will create greater <br />disturbance and potentially cause site erosion. As stated, the normal practice will be to reduce <br />all slopes, but possible exceptions might include benches or road cuts that have already <br />revegetated or stabilized or which can only be graded by cutting new access, provided <br />however that the existing face is stable and not eroding. <br />Access Roads: Road closures and reclamation will consist of grading shoulders, cuts, <br />and ditches, if necessary, to reduce slopes to 2:1 or less. In conjunction with grading, water <br />bars will be placed at select locations to prevent buildup of runoff down the road surfaces; the <br />numbers of bars will be minimal to avoid additional disturbance. The road surfaces will be <br />scarified to relieve compaction and to provide a seed bed. Upon completion of grading and <br />scarifying, the disturbed areas will be seeded by broadcast seeding, followed by light <br />harrowing or dragging to embed seeds. <br />Reclamation Seed Mix: Adjoining mine sites in the local area have differing <br />reclamation seed mixes in the permit reclamation plans. The Operator proposes to <br />"standardize" the seed mix to be used in the area of the Sunday group of mines. The proposed <br />seed mix is derived from the existing mixes in the permits held by the Operator and from <br />recent experience with the proposed general mixture. The following seed mix is proposed: <br />Western Wheatgrass: <br />Crested Wheatgrass: <br />Indian Ricegrass: <br />Yellow Sweet Clover <br />Four Wing Saltbush: <br />Sand Dropseed: <br />61bs/acre PLS <br />6 lbs/acre PLS <br />3 lbs/acre PLS <br />1 lb/acre PLS <br />41bs/acre PLS <br />0.21b/acre PLS <br />