Laserfiche WebLink
Relief from primary TSS at Outfalls 007A: Please see 007A Exceedence Report attached to this <br />submittal for more detail and back-up information. <br />Rainfall was recorded at Colowyo on September 23 and 24, 2007, two days prior to the day sampling was <br />completed at this location. Inflow into this pond is primarily in the form of storm water runoff at this time. <br />Precipitation received from Colowyo's three monitoring locations averaged 0.71 inches on September 23 <br />and 0.10 inches on September 24. $ is Colowyo's firm belief that the discharges occurring on September <br />25, 2007 were a direct result of a precipitation events (rain) creating surface runoff. Additionally, please see <br />the attached climatological data for additional information. Colowyo believes this specific incident of <br />exceeding primary TSS limitations is due primarily to increased storm water runoff caused by storm events <br />the two days prior to the day of sampling. <br />Colowyo performs PE reviewed pond inspections of all NPDES ponds on a quarterly basis as mandated by <br />CDRMS/Colowyo Permit requirements. These quarterly inspections are reviewed by CDRMS staff and <br />specific guidance, maintenance issues, and improvements are discussed as necessary with Colowyo's <br />assigned CDRMS inspector (currently James Stark). <br />In an effort to further minimize issues with TSS limitations, Colowyo is in communication with G$ Betz in <br />order to identify any acceptable products on the market that could be more effective at settling out <br />suspended materials. Testing is in progress to evaluate the relative effectiveness of these products. <br />Colowyo is currently evaluating opportunities for improving the manner in which storm water enters the <br />pond. Modifications to in-pit drainage structures and conveyance ditches may be warranted if opportunities <br />for minimizing particle/sediment loading are discovered. This is an on-going process and improvements <br />will be implemented as they are identified. <br />Because Colowyo's ponds are flow-through treatment ponds and not containment ponds, it is not possible to <br />impound waters for an extended period of time once discharge levels have been reached. These ponds were <br />designed to treat storm water inflow for settleable solids to a level of 0.0 ml/1 during a 10-year 24-hour <br />storm event. <br />It is Colowyo's belief that due diligence, good faith efforts and in-house procedures and practices were <br />followed prior to, during, and after the exceedence of TSS limitations reported from the September 25, 2007 <br />sampling and humbly request the grant of a waiver from said limitations as allowed by our CDPS Permit at <br />your discretion. <br />Thank you for your consideration. Please feel free to contact me if you have any questions or concerns. I <br />can be reached at{970) 824-1532. <br />S~~ <br />Tony Tennyenny o~ <br />Environmental Engineer <br />Encls. <br />Copy: Jim Stark (CDMG) <br />NPDES Reports Binder w/encl <br />C.F. 21.1.2 w/encl <br />Colowpo Mine • 5731 State Highway ] 3 • Meeker, Colorado 81641 <br />T +1 970 824 1500 • F +1 970 824 1504 • www.rtea.com <br />