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RULE 2 PERMITS <br />Reclamation Report within the Topsoil Volume Inventory section. The topsoil depth verification program <br />is not intended nor should it be used as a topsoil volume verification method as the volume of topsoil will <br />be planned, monitored and verified through load count, time card coding and engineering plan designation <br />of placement of the material on a reclamation unit basis. Overall topsoil balance oversight is performed <br />and reported annually in the Annual Reclamation Report. The overall goal of both the Division and <br />Colowyo is to replace the entire resource in a manner that promotes the likelihood reclaimed areas will <br />meet the success criteria for Phase III Bond Release after the required liability periods and thereby create <br />reclaimed lands that reflect the desired post -mine land use (grassland and sagebrush steppe). <br />Reapplied topsoil will be left in a rough condition to help control wind and water erosion prior to seeding. <br />In the case of scraper - applied topsoil, dozers usually cross -rip along slope contours at intervals of about <br />50 -75 feet to provide additional surface roughness. Also, contour furrows are almost always put in place <br />when scrapers are utilized to minimize any sheet flow from the topsoil surface. Due to the specific <br />equipment used for the Sagebrush Steppe areas, topsoil will be left in a more smooth condition to ensure <br />proper seeding depth as described in the text. Any topsoil put into final position with a dozer will by <br />practice be in a state of rough condition. Previous roughening efforts at Colowyo have been extreme, <br />leading to difficulties in placing seed at biologically viable depths. The addition of more contour furrows <br />will reduce sheet flow and moderating the roughness will allow a greater percentage of seed to germinate <br />and provide ground cover that will also alleviate rilling and sediment control issues. As Coloywo <br />transitions into areas of steeper slopes, density of cross ripping will be tightened to increase surface <br />roughness and more contour furrows will be used to break up the slopes and minimize sheet flow <br />conditions and reduce any concentration of flow from rain/snowmelt events. Seedbed preparation, other <br />surface manipulation practices and seeding will be completed primarily during the fall months. Contour <br />furrows, approximately 4 -6 inches deep at the deepest point and 20 -25 inches wide, which have been used <br />on slope areas very successfully during the past several years, will be used to reduce erosion potential, <br />conserve moisture, and maintain site stability until vegetation is sufficiently established. The size of the <br />furrows may be increased if necessary to control erosion, and the distance between the furrows will vary, <br />but will be approximately 10 to 75 feet along the slope. Small rock check dams may also be used where <br />appropriate to aid in control of erosion both prior to seeding and if necessary, after an area has been <br />seeded. <br />Colowyo will utilize the planned post -mine topography (PMT) to help identify candidate (and prime <br />candidate) areas for targeting Sagebrush Steppe post- mining communities. Key to this analysis will be <br />considerations for the risk of erosion and for long -term stability. One such "threshold" value to be used <br />for this analysis will be a slope break at 10% gradient. Slopes greater than 10% will be considered too <br />risky to make attempts at targeting shrub communities, largely due to snowpack runoff scenarios that can <br />often lead to serious erosion and stability failures. For example, snowmelt runoff in the early 1980s <br />caused widespread and severe down - cutting of the natural drainages to the immediate west of Colowyo. <br />Unless proven otherwise by hydraulic and /or erosion modeling, slopes less than 10% will be identified as <br />candidate locations for shrub community establishment. Another "threshold" value to be used in the <br />PMT analysis is the size of units that may exhibit slopes 10% or flatter. Areas small in aerial extent (e.g., <br />less than about 5 acres) will not be identified to receive shrub - conducive metrics. Only those areas that <br />are larger will be identified. The exact size cutoff will be at the discretion of the reclamation coordinator, <br />however, a practical limitation must be defined given the complications realized by the change in <br />revegetation targeting measures. <br />Where Sagebrush Steppe revegetation will be targeted, Colowyo would apply shallow lifts of topsoil (< 6 <br />inches, ideally 4 inches). Where ideal spoil conditions are encountered, special effort will be made to <br />place very minimal topsoil layers (nearly zero). The size of these areas must be small in order to ensure <br />the potential erosion potentiai created by this activity does not negatively impact areas down slope. The <br />Division will be informed of any instances of "nearly zero' topsoil laydown areas prior to or during <br />Collom — Rule 2, Page 108 Revision Date: 9/28/11 <br />Revision No.: PR -03 <br />