Laserfiche WebLink
COLORADO DEPARTMENT OF HEALTH, <br />Rationale - Page 7. Permit No. <br />V. PERFORMANCE HISTORY <br />Water Quality Control Division <br />CO-0032115. <br />2. State Sampling: State sampling results for Trapper Mine are <br />summarized in Table V-2 for the period of March, 1987 to the <br />present. No violations were reported. <br />Table V-2 -- Summary of State Sampling Results <br />Parameter Disch. Point Value No, of Samples <br />Flaw, MGD 002 0.09 1 <br />Flow, MGD 005 0.06 1 <br />TSS, mg/1 002 13 1 <br />TSS, mg/1 005 12 1 <br />T. Iron, mg/1 002 0.58 1 <br />T. Iron, mg/1 005 0.14 1 <br />pH, s.u. 002 7.4 1 <br />pH, s.u. 005 8.4 1 <br />Oil and Grease, mg/1 002 None Visible 1 <br />011 and Grease, mg/1 005 None Visible 1 <br /> <br />B. Compliance with Terms and Conditions of Previous Permit <br />A review of the information available to the Division has shown <br />several permit violations for pH (see Data Summary, Table V-1). The <br />permittee has determined that these violations, which occur during the <br />summer, are due to algae blooms in the ponds, which can raise the pH. <br />The permittee used an herbicide, Cutrine, for a short time, but <br />discontinued its use at the Division's request due to the presence of <br />copper in the compound. Since then, the permittee has installed C02 <br />bubblers to lower the pH. This has worked for the most part, but some <br />violations still occur. <br />Given that the elevated pH is due to the algae, and not the mining <br />activities, this permit will allow a pH variance at discharge points <br />001, 002 and 005, from June through September, with the maximum <br />allowable pH limit set at 9.5 s.u. The new limit is based on the <br />maximum pH recorded by the permittee at these points while using a <br />C02 bubbler. The use of a C02 bubbler oa the effluent will be <br />required as a Best Management Practice at the site whenever the <br />variance is applied. The permittee may develop other appropriate <br />measures to control pH, such as the use of appropriate algicides, <br />aquatic life, etc. However, such measures in addition to or instead <br />of the C02 bubbler must be approved by the Division via a permit <br />amendment prior to their use. Since the receiving streams are usually <br />\ dry and do not have strict classifications, no impacts to water <br />\ quality are expected from allowing the variance. <br />., <br />Y'... <br />t.'# <br />:. ,.. , <br />