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iiiiiiiiiiiiiiuiii <br />999 <br />STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Depanmenj of Natural Resources <br />1713 Sherman 51., Roam 215 <br />Denver, Colorado 80203 <br />Phone: 13031 88fi-3567 <br />FA%:1307)8)2-8106 <br />DATE: July 5, 1996 <br />TO: <br />FROM: <br />RE: <br />Erica Crosby <br />Larry Routten <br />Colowyo Mine Cover Success Standard <br />I~~~~ <br />DEPARTMENT OF <br />NATURAL <br />RESOURCES <br />ftoy Romer <br />Governor <br />dames 5. Lochhead <br />Executive Dueaor <br />Michael B. long <br />Division Director <br />During the mid-term review, a question arose regarding whether the <br />success standard for cover was based on total or herbaceous cover. <br />It appears the original specification for total cover was revised <br />during the 1987 permit renewal to indicate herbaceous cover would <br />be used to determine vegetative success. I checked the 1980 <br />baseline data in the Colowyo permit. If revegetated areas were <br />compared to the reference areas in 1980 (when they were sampled), <br />the success standard for the mine would require that total <br />vegetative cover on revegetated areas be at least 90$ of 35.3$, or <br />31.8$.* <br />Most or all of the coal mines in northwest Colorado have <br />established revegetated communities with significantly more <br />vegetative cover than 31.8$. Based on my observations of reclaimed <br />areas, erosion control on reclaimed hill slopes is often marginal <br />prior to the establishment of more vegetative cover than this. I <br />would be concerned about establishing a vegetative cover success <br />standard as low as 32$. I recommend that we postpone resolution of <br />this question until Dan Mathews has a chance to visit the Colowyo <br />reference areas during his August inspection trip. After looking <br />at the reference areas to see how much herbaceous and canopy cover <br />is present, and possibly reviewing some revegetation data from <br />Colowyo, we should be able to decide whether to use total or <br />herbaceous cover with some rational basis. <br />Split the remaining 3.2$ equally between the two communities <br />and, <br />Mountain shrub=43.3$ of disturbed area; 1980 herbaceous cover= <br />41.8$. <br />Sagebrush= 53.3$ of disturbed area; 1980 herbaceous <br />cover=30.2$. <br />(41.8)(.449)+(30.2)(.549)=35.3$ <br />cc: Dan Mathews <br />C:\wp51\070596 <br />