Laserfiche WebLink
except in one minor area at the nose of a small ridge where a minor tension crack was observed. This <br />minor tension crack is approximately 20 feet in length and varies from Yx to 2 %: inches in width. • <br />See Attachment 13-14, Haul Road B Extension Instability Investigation, for documentation of existing <br />conditions including photographs of the area were topsoil was removed and the existing Topsoil <br />Stockpile H. A confirmation site visit and review was conducted in July 1999 and concluded that no <br />landslides exist in the proposed disturbance area. The results of this confirmation study are included <br />as Attachment 13-6A, Ground Stability Investigation, Yoast Mine and Vicinity. <br />If it is constructed on natural ground, there are portions of the Haul Road B Extension that will exceed <br />10% for greater than 300 feet. Given the existing steep terrain in the "neck" area and SCC's <br />commitment to minimize total disturbance, the steep grades can not reasonably be eliminated. The <br />only feasible means of eliminating the over-steepened road segments would be to increase the overall <br />road length and add multiple curves or switchbacks. This option is not operationally or <br />environmentally acceptable since the curves or switchbacks would reduce haulage safety and speeds <br />and increased road length would increase surface disturbance. In order to minimize the impact of the <br />steeper sections, culverts will be placed to reduce peak flows from the runoff along the haul road and <br />surrounding disturbed areas. However, erosive velocities will still exist during a 10-year event. Any <br />minor erosion caused by from these infrequent events can be effectively dealt with by routine <br />maintenance of the haul roads and ditches. Haul Road R Extension will-be constructed within the <br />limits of pit disturbance. Runoff from this area will report to Pond 10. • <br />No part of any haul road is located in the channel of an ephemeral stream draining a watershed of at <br />least one square mile, intermittent or perennial stream unless specifically approved by the Division. All <br />stream crossings will be made using culverts. Haul roads are located to minimize downstream <br />sedimentation and flooding. <br />Stream Buffer Zones. Neither the existing or proposed haul roads are located within 100 feet of a <br />perennial stream or stream with a biological community as defined by Section 4,05.1813) of the <br />CDMG regulations. Road crossings of both Annand Draw and Scotchmans Gulch consist of culverts <br />riprapped at the inlets and outlets. When road ditches route runoff to existing channels, riprapped <br />downdrains are constructed to prevent additional contributions of suspended sediment (see lab 16, <br />Protection of the Hydrologic Balancer <br />Design and Construction. The design of the haul roads incorporate the demand for mobility and travel <br />efficiency, based on the geometric criteria appropriate for the anticipated volume of traffic, weight and <br />speed of the vehicles to be utilized. The design and construction or reconstruction of haul roads not <br />within the estimated disturbed area are certified by a registered professional engineer. <br />The portions of the proposed haul roads not within the estimated mining disturbance areas are • <br />designed and constructed or reconstructed as described late=.r in this section under "Drainage." <br />PR-02 12a Revised 03/05 <br />