Laserfiche WebLink
TABLE 1.0 ANALYTICAL SUMMARY TABLE BIG FIVE DISCHARGE SAMPLES <br />Metals concentrations expressed in mkonramslLiter <br />sampling Event As Cd Cn Mg Ma Ph Zn <br />1985 Phase I RI 10 48 1710 NAY 19,700 91 9770 <br />1989 Phase II RI 10 27 690 NAF 18,800 5 9100 <br />2001 CDPHE NAF 24 1300 NAP 32#7M NAF 910 <br />2005 UOS a? 2 20 2960 0.1 191500 16 7610 <br />rlakl?e Water MCI. <br />E 10 3 2 <br />inidn Water MCLC - 1300 15 <br />Second MCL <br />M 100 SO Soo <br />AS <br />&C <br />We NEC1W 91 5 0.413 319 <br />j 0.07 100011493 412 4?1200 <br />NAP m Not Analyzed For <br />MCL - Marianna Contaminant Level <br />MCLC-Maximum Contaminant Level Goal <br />NEC - No Effect Concentrations are aetal concentrations at which aquatic life does not sutler any toile effects <br />(1) UOS --START contractor for EWs.Emergency Respoase Team <br />(2) WQCD - aquatic standards for Clear Creek Segment 2 <br />In the event there is infiltration into the 11roundwater table the net quality could only significantly improve <br />A current sampling of the Big 5 Tunnel discharge also follows in this Exhibit C. <br />This sampling was done over a period of time from 1985 - 2009. It becomes apparent that the reported metals <br />concentration varies widely. Rationale for this can be explained by variation in rainfall amounts preceding the <br />sampling and the concentration of that rainfall in different areas of differing mineralization. This wide variability <br />can not be attributed to active mining operations because we are not aware of any within this drainage area over this <br />period of time. <br />Tailings Impoundment Construction: <br />The impoundment and composite liner system is to be constructed on crystalline metamorphic and igneous rocks <br />with minimal hydraulic conductivity. A concrete barrier will be installed upon the up gradient face of the first earth- <br />fill terrace to minimize leachate through the stricture (see Exhibit E). The natural slope, upon which the fill will <br />reside, is slightly less then 3h:ly (f 18°). <br />Generally speaking, the Tailings Impoundment will be built up in a series of five benches utilizing an upstream <br />hydraulic placement and hydraulic classification method. A maximum of 40 square feet of new embankment face of <br />minimal height (10-12 ft. per year), built with the coarse fraction, will be formed daily giving more than adequate <br />time for consolidation and draining. A maximum slope of 1.5h : Iv (f 33.7°) will be maintained at the embankment <br />free face. <br />Design guidance was taken in part utilizing Steven G. Vick's Planning, Design, and Analysis of Tailings Dams, <br />1990 and the US Army Corps of Engineers (USAGE) Slope Stabili4,, EM 1110-2-1902. These authoritative works <br />are cited in many EPA design and regulatory mandates. <br />Page 15 of 37