Laserfiche WebLink
<br />Technical Revision No. 18 <br />Bear ~3 Mine <br />Page 2 <br />6. I reviewed all ditch sizings and found them to be <br />adequate with the exception of the mine bench access road <br />ditch. The ditch has been sized for flow from Areas #2, <br />3, and 4. However, Area ~'1 also flows into the ditch, <br />which increases the discharge to 7.91 cfs and according <br />to the calculations provided on page 11-6, the ditch is <br />undersized. I also modeled this ditch using SEDCAD with <br />the increased discharge and the ditch was not large <br />enough. I would recommend that Bear revise this <br />calculation and increase the size of the ditch in the <br />field. <br />7. The pond should continue to be adequately sized. As I <br />stated earlier, the method of peak flow calculations is <br />very conservative and from review of the SEDCAD runs for <br />only Areas #1, 2, 3, and 6, the total runoff volume <br />totals 0.44 acre-feet and the pond is designed for 0.9 <br />acre-feet. I do not believe that water from Areas #4, 5, <br />and 7 would exceed the 0.75 acre-feet available for water <br />storage. <br />Upon increasing the size of Culvert #3 and the mine bench access <br />road ditch, I would recommend that you approve this revision. <br />Please let me know if you have any questions or should require <br />anything further. <br />cc: David Berry <br />CEJ/033TR18SS <br />