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<br />(Page 2) <br /> <br />NINE ID ~ OR PROSPECTING ID f M-79-216-Hit <br />INSPECTION DATE 11/12/96 INSPECTOR'S INITIALS ACS <br />On 9/10/96, the Division of Minerals and Geology (Division) prepared a list of maintenance <br />items for the Deer Creek Quarry, and provided this list to the operator, Rocky Mountain Rock <br />Products, and other interested parties. The list of required maintenance items was primarily <br />derived from the observations made and the corrective actions specified during the Division's <br />Bite inspect Lone dated 3/2/95 and 4/10/96. Western Hohile (parent company to Rocky Mountain <br />Rock Products) provided details on how the maintenance items would be completed in a Letter <br />dated 10/4/96. This inspection was conducted to evaluate the Western Mobile proposal for <br />completion of the required maintenance items. A number of proble~ee (designated in the report <br />by the letters "PB") were identified during this inspection. These problems are described <br />in the 'observations' section of this inspection report, and are restated on the last page <br />of the report with deadlines specified for the completion of corrective actions. <br />Item 1 <br />Maintenance item fl called for stabilization of the elope above the first reach of the paved <br />access/haul road (below the first switchback). This elope hoe settled approximately one foot <br />ae evidenced by cracks and unevenness in the paved access/haul road above the elope. The <br />operator hoe proposed diversion of runoff to a ditch on the uphill aide of the access/haul <br />road to minimize infiltration of water into the elope, thus alleviating any further <br />settlement. It appears that the elope settlement that hoe occurred ie at the interface of <br />cut and fill in the road cross-section. A certain amount of settling at the cut-fill <br />interface would be expected for any road of this type, and ie a maintenance item for any mine <br />or quarry that uses cut and fill zoade. Ae such, the Division agrees with the operator's <br />proposal to divert runoff into a road aide ditch. However, the following problems exist with <br />the operator's approach: <br />1. There ie currently no road aide ditch to divert runoff into. A roadside <br />ditch needs to be installed that will convey runoff generated by the 10-year, 24-hour storm <br />event. <br />2. The operator proposes to divert runoff that currently rvns over the asphalt <br />road by constructing a 12 to 18 inch directional dike on the road, with the dike to be <br />constructed from clean-out taken from the sediment pond below. A dike constructed on asphalt <br />from the silty materials available in the sediment pond would likely be washed out during an <br />intense rain event. Alen, dike constructed on the road would lessen the utility of the road. <br />A better solution would be to use across drain such ae that which exists at the scale house. <br />Any cross drains that are installed would have to be capable of passing the 10-year, 24-hour <br />storm event. <br />3. The uncontrolled flows off the asphalt road onto the fill elope below the <br />first switchback hoe created an erosion gully that must be filled in and revegetated. The <br />cross drain at the scale house hoe created an erosion gully on the elope at the cross drain <br />outlet point. This, and any other crone drain and culvert outlets need to be stabilized <br />against erosion (see PB f4 on the last page of this report). <br />4. The cracks in the asphalt pavement need to be sealed to minimize <br />infiltration into the destabilized elope (see P8 fl on the last page of this report). <br />Ztem f2 <br />The operator proposal to stabilize rill erosion on the topsoil stockpile ie acceptable. This <br />stabilization work should be completed by the date specified under Pe ~3 on the last page of <br />this report. <br />Item 3 <br />Maintenance item f3 calla for clean-out end repair of the sediment pond at the low end of the <br />site. The operator hoe proposed using a baekhoe to bail out the pond. Inspection of the <br />pond during this site visit has led to the conclusion that the sediment pond in its current <br />condition is inadequate to control releases of suspended solids to adjacent Deer Creek. The <br />embankment for the pond consists of an irregular pile of sand and gravel with a pipe running <br />