Laserfiche WebLink
• • <br />RECEIVED <br />Rirnrock Mine Sediment Pond Certification OCT 13 1999 <br />Division of Minerals 8 Geology <br />The site inspection was conducted on September 2, 1999. It was a partly sunny day of 74 <br />degree temperature and it appeared that precipitation had occurred in the previous week. <br />Water was present in the lowest portion of the pond, covering an azea of approximately <br />25 ft x 30 ft. The pond itself was free of any type of problem with stability or erosion. <br />Engleville Gulch was dry. The pond is to be left as a permanent vnpoundment for use in <br />the grazing operation. <br />The following items were checked to see if they coincided with the design shown in the <br />mine perrtvt application. I, Greg Lewicki, did the pond design in Mazch of 1990. <br />1) Constructed Elevations: The elevations listed below were checked with a precision <br />level and stadia rod: <br />-Dewatering pipe inlet <br />-Dewatering pipe outlet <br />-7'op of Dam <br />-Bottom of Emergency Spillway <br />-Toe of Dam (outside and inside) <br />-Bottom of Pond <br />-A number of points within the pond <br />All elevations were found to be acceptable. The inlet to the principal spillway was placed <br />at a slightly higher elevation to allow more sediment storage. The ]0 yeaz - 24 hour <br />runoff storage was still present above the principal spillway. <br />2) Width of Emergencv Spillway Design: 12 feet. Measured: 12.2 feet. <br />3) Depth of Emer ency Spillway Design: 1.55 Feet. Measured: 1.60 feet. The spillway <br />showed no evidence of flow or any signs of erosion or other instability. <br />4) Width of tom of Dam Design: 10 ft. Measured: 10.2 ft - 10.6 feet. <br />5) Principal Spillw~ Design: 4.0" pipe placed in compacted embankment. Measured: 4" <br />steel pipe placed in compacted embankment. Extensions on this pipe were added to both <br />sides so that the embankment could be widened. Some black plastic hose was also present <br />near the spillway at the time of the inspection but was not functional. The principal <br />spillway pipe was completely free of debris and was functional during the site visit. <br />