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Memo - Permit No. C-81-019 - 2 - July 7, 1993 <br />(1) continued <br />An operator, then, would achieve compliance with this rule by <br />selectively placing stockpiled materials on a stable surface within <br />the permit area, where with all four of these protective measures <br />could be accomplished. <br />Based on the photographs provided, it is apparent that on <br />May 5, 1993, topsoil had been previously bulldozed onto downhill <br />undisturbed areas by the operator Prior to the inspection. This <br />practice led to the condition in which topsoil from stockpiling areas <br />was eroding away through these dozer slots during spring <br />snowmelt/runoffs. As such, an event which 4.06.3 was designed to <br />prevent, occurred. <br />(2) Assessing the duration and extent of actual or potential damage, in <br />terms of area and impact on the environment, required determining <br />first what the damage was. As topsoil is necessary for successful <br />achievement of approved revegetation standards, of approved surface <br />water quality standards, and of approved post-mining land use(s), <br />damage appears to be in the form of potential future substandard <br />reclamation. <br />Duration of the potential damage could, in effect last years, until <br />neighboring undisturbed or reseeded vegetation could invade the <br />substandard area enough to revegetate it to approved standards. <br />Given the climate of northwest Colorado, substandard reclamation <br />could exist for a minimum of one year. <br />The extent of the potential damage (the substandard reclamation) was <br />estimated at 15,974.4 feet. This was derived from two figures. The <br />first came from assuming an erosive loss of topsoil from all three <br />down slots at a combined total rate of 0.001 cfs. This was <br />multiplied by a period of twenty-three days, from May 5, 1993 (the <br />date of the inspection during which the problem was first noticed and <br />the NOV issued) to May 27, 1993 (the date a second inspection <br />verified that an upland diversion structure had been installed). <br />This resulted in a volume of 1987.2 cubic feet of lost topsoil. <br />The additional volume came from estimating the size of the <br />three dozer cuts at four feet deep by ten feet wide by 50 feet long. <br />This added 6000 cubic feet to the 1987.2 cubic feet fora total of <br />7987.2 cubic feet. Re spreading to a depth of six inches, an area of <br />15,974.4 square feet could have been reclaimed with this lost topsoil. <br />Based on the one year duration and 15,974.4 square feet of extent of <br />potential substandard reclamation, seriousness is established at low, <br />and set at E250.00. <br />