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2011. Results of this study will contribute to revegetation methods in the future. <br />C. Mulching <br />In the original permit application, Colowyo proposed that mulch was not required on slopes less <br />than 4:1. This discussion is summarized in the original findings document and starts on page <br />2.05 -55 of the Permit. The Division approved this proposal at that time with erosion control prior <br />to vegetative establishment to be provided by contour plowing. Monitoring of mulched versus <br />non - mulched areas was required as part of Colowyo's Annual Reclamation Report. In addition, a <br />stipulation was added to the permit requiring the use of mulching if excessive erosion does <br />develop. <br />Subsequent monitoring data showed that mulching was not necessary for erosion control or plant <br />establishment. As a result of the permit renewal process in 1987, both mulching and the <br />monitoring program were eliminated as requirements. The above - mentioned stipulation was at <br />that time incorporated into the Permit. <br />D. Revegetation Success Standards <br />Prior to initial disturbance at Colowyo, Colorado State University and the Soil Conservation <br />Service Upper Colorado Plant Materials Center conducted studies, in cooperation with Colowyo, <br />to determine appropriate seed sources, species composition and revegetation practices to ensure <br />reclamation success at the mine site. Results of the studies conducted by Colorado State <br />University are included in Exhibit 10, Volume IV, of the permit. No final report has been issued <br />from the SCS Plant Materials Center. <br />Methods for evaluating vegetative success are found in Section 4.15 of the original Permit <br />volumes, and in Section 2.04. 10 and 4.15 of Volume 12, submitted in association with PR -2. As <br />part of this process, two reference areas have been established for the determination of <br />reclamation success for the disturbed areas other than those associated with the Collom project <br />area. One reference area represents the sagebrush community while the other represents the <br />mountain shrub community. Cover data was collected by measuring five random points along <br />100 -foot long transects. A ten -point frame was used to measure each of the five points. <br />Production values were measured by clipping 30cm x 30cm plots at each of the five points along <br />the transect used to measure cover. Data from 1976 reflects air dry weight while 1988 data was <br />measured with 60cm x 60cm plots with plant biomass being oven dried prior to weighing. <br />Based on herbaceous cover and productivity from the sampled reference areas, the revegetation <br />success criteria for the disturbed areas other than those associated with the Collom project area <br />are as follows: <br />Herbaceous cover will be at least 90 percent of the cover measured in the reference area <br />with a 90 percent statistical confidence level. Herbaceous productivity for revegetated <br />Colowyo Coal Mine C1981 -019 PR -03 62 April 10, 2013 <br />