Laserfiche WebLink
<br />A three-dimensional figure (2.3.32) was created to help understand the geometry of the hydraulic <br />structures and flooding over the tailings piles. The view looks east, and purple lines represent <br />two-foot contours derived from the topographic survey. Several 40-foot contours on the east <br />side of the canyon have also been added. Tan boxes represent structures in the area, and the <br />Commodore flume and pipe are colored grey. The manhole access and vent to the pipe were also <br />added. The height of the 100-year flood level from the HEC-RAS analysis is shown as blue. <br /> <br />Hydraulic analysis showed that the Commodore pipe cannot pass high flows. Water levels will <br />rise, filling the depression near the pipe access and then overtopping the tailings pile. The flow <br />down the very steep side of the tailings pile will be highly erosive and could potentially wash <br />tons of mine tailings into the Willow Creek channel. Fine tailing sediments would probably be <br />carried by the flood into the Rio Grande. The constriction of the flume entrance will also cause <br />overtopping onto the tailings. However, the flooding should generally be restricted to areas <br />surrounding the flume. <br /> <br />A plan view of inundations for various flood return intervals is shown in Figure 2.2.33. The <br />middle level of the tailings pile will be overtopped initiating at the 25-year flood level. The 10- <br />year event will cause filling of the depressed area with water, but the added head of water will <br />pass the flood flow before the tailings are overtopped. Overtopping of the flume entrance will <br />also initiate at the 10-year flood level. <br /> <br />Figure 2.2.32. Three-dimensional view of Commodore Mine and 100-year flood level <br /> <br /> <br />2-34 <br />