Laserfiche WebLink
<br /> <br />SLOPE STABILITY <br />The entire tract is relatively flat with only about 10 feet of relief across the more than t/2 mile long <br />tract. Therefore no hazard exists to the immediate area due to landslide or mass earth slides. Due to <br />undercutting from the Colorado River, areas located in the Wildlife Refuge, directly south, appear to <br />show some evidence of mud slides. This does not appear to be an immediate concern of the Railhead <br />Industrial Park. <br />The Bureau of Reclamation recommends slopes of 1:1 (horizontal to vertical) for these types of <br />excavation operations. For a permanent borrow pit, or for reservoir area back slopes las the northwest <br />section of this tract shall be reclaimed as a pond) the Bureau of Reclamation recommends a slope of <br />1.5:1. But in areas where the public shall have access, 3:1 slopes are advised. <br />It is our understanding that the pit will be mined utilizing 2:1 side slopes; and , at closure, the northern <br />approximate 2/3 of the pit area is to be reconstructed at 3:1 slopes. The southern approximate t/a is <br />planned to be filled. <br />CONCLUSION <br />Findings related to the Railhead Industrial Park and the tract of ground proposed by United Companies <br />for excavation operations, may be summarized as follows: <br />The Billings Silty Clays have qualities which will be caustic to concrete structures. If applicable, sulfate <br />resistant cements should be used. Excavation for alluvium will require a constant means of de-watering. <br />No appreciable landslide hazards exist on the immediate property. Earthquake hazards are listed as low, <br />and with the proposed 2:1 mining and 3:1 closure slopes, present earthquake magnitude will have no <br />significant effect. Numerous utilities and some man-made structures are on or near this plot of land. <br />All man-made structures must be accounted for with respect to CRS 34-32-115(4). <br />The concrete irrigation ditch and adjacent dirt access road to the Wildlife Refuge is to be rerouted along <br />the northwest utility easement and enter the sanctuary at the far northwest corner. The train spur track <br />and verious~utilitie~ will be removed from the site. The USGS benchmark will be relocated and <br />established per the proper authorities. The 44 foot drainage easement is planned to be removed and <br />the runoff directed into the pit. <br />5 <br />