PERMFILE44249 - Laserfiche WebLink

Home Browse Search

Coulson Excavating Company, Inc. - Bonser Gravel Pit Exhibit E -Reclamation PLtn The goal of reclamation will be to restore all disturbed azeas (gravel pit and overburden stockpile locations) to agricultural use (Exhibit F). Apre-existing pond will remain in the southwest comer of the permit area. This pond was constructed in 1976 by Latimer County. Land Use Primary Iand uses near the vicinity of the mine include farming, transportation, coral residential, and recreational. A county road and railroad aze located north of the proposed mine, and to the northeast two parcels of land are owned by separate landowners. These parcels aze used for coral residential and agricuhural purposes, as well as the Iand dvectly to the west. The Big Thompson Ponds State Wildlife Area and Big Thompson River corridor are located dvectly to the south of the proposed come, and the Big Thompson River corridor continues along the eastern boundary. Reclamation Sequence Reclamation will begin after the first five years of operation. Overburden from pit 1 will be backfilled dvectly into pit 1 after lining with weathered Pierre shale. Each subsequent pit will be backfilled prior to the mining of the next pit Final grading and re-vegetation will occur after the last of the gravel is extracted. Grading contours, at a 2:1 slope, are shown in Exhibit F. Pit Liner Design and Specification The purpose of this section is to provide design specifications for the pit liners. The goal is to design a post-mining, compacted clay liner that will prevent groundwater leakage into the pit at a rate Beater than or equal to .03 ft3 /day / ft=. The source for the compacted clay liner will be a 3 -5 ft. thick weathered zone of Pierre shale occurring 17.5 ft. below ground surface. Textually and mineralogically continuous in a lateral direction, the Pierre shale is flat lying in this area (Porter, 1976). The weathered zone is a friable silty clay consisting of illites and small amounts of smectites (Gill et al, 1996). Source Material Samvline/Laboratorv Analysis A 5 gallon sample of weathered Pierre shale was collected from a gavel operation to the west. Collected from the upper 3 to 4 ft. of the weathered horizon, the shale appeazed very consistent with respect to color and texture with that of the weathered shale within the proposed excavation area. Moreover, personal communication with local excavators and drillers confirm the consistency of the Pierre shale throughout eastern Loveland. This consistency is most likely due to the flat lying nature of the shale in this region. If the source material shows any variability with respect to color, texture, or content from the sampled material, a full suite of geotechnical tests will be performed.