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Surface Water Control and Containment for Staging Area <br />Surface water runoff within the berm around the staging area will flow to the northeast to <br />the detention pond as described in the following paragraph and illustrated on Map C-2(b) <br />and Photograph 9. <br />The estimated area that could potentially discharge to the Monogram pit was determined <br />by GIS mapping over the topographic contour lines that indicated surface flow would be <br />in the northeast direction to the planned detention pond. This bermed staging area was <br />determined to be approximately 32,116 square feet. The interior bermed area for the Ore <br />Bins and Loading Area is approximately 3,400 square feet and is designed for total <br />containment; that area was deducted from the staging area calculations, for a net area of <br />28,716 square feet. The design scenario would be that all of the water that falls on the <br />area from a 2-year 24-hour event plus the 10-year 24-hour event would require <br />containment. The total of both storms would require containment of 7,653 cubic feet or <br />57,246 gallons (based on 3.2 inches of rainfall, NOAA ATLAS 2, Volume III, Figures 26 <br />and 28). The storm water run-off from the staging area will flow to a detention pond as <br />shown on Map C-2(b). The purpose of the detention pond is to accumulate and control <br />storm water runoff, minimize sediment transport, and prevent offsite erosion. The <br />detention pond will reduce the velocity of the storm water leaving the site and will allow <br />sediment entrained in the water to drop out. The estimated capacity of the detention pond <br />is 4,750 cubic feet. The detention pond has been designed to contain only a portion of <br />the volume of run-off from a combined 2-year 24 hour and 10-year 24-hour event while <br />maintaining at least 0.5 feet of freeboard while trapping sediment from the area. <br />However, the detention pond will be unlined and constructed in semi-permeable site <br />materials that will allow infiltration and seepage. The pond constructed at the northeast <br />edge of the bermed area will be dug in the native soil in the area. It will be 38 feet long x <br />20 feet wide at the bottom by 5.5 feet deep with 1:1 side slopes. The outfall will be <br />armored with native rock rip-rap and will be fenced for wildlife protection. <br />Certification Statement <br />By means of this Professional Engineer Certification, I herby attest to the following: <br />I have reviewed the information provided in the plan and the design as described <br />above; and I have determined that the design will detain surface water run-off <br />from areas affected by the Monogram mining operation prior to its release from <br />the staging area into the natural water drainage system. <br />Thomas J. Jaw) <br />Printed Name of Registered Professional Engineer <br />Signature of Re to d Pr essional Engineer <br />Date: March 9, 2009 Registration No.:1837 State: Wyoming_