HYDRO29057

• Permit No: M1988112
• IBM Index Class Name: Hydrology
• Doc Name: TABLE OF CONTENTS
• Media Type: D
• Archive: No

COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division
Rationale -Page 11 Permit No. CO-0045675
VI. TERMS AND COND/T/ONS OF PERM/T
A. Deterntination ojEffiuent Lirnita(ions (Cont.)
1. Effluent Limitatiats: (Cont.)
Table V/-Ic -Effluent Limitations, Discharge Point OOIc
Parameter Limitations Rationale
Flow, MGD (gpm) 0.158 (110) a/ Design/Flow Assessment
Total Suspended Solids, rng/I 30 / 45 e/ Stare Effluent Regulations
Oil and Grease, mg/l 10.0 d/j/ Slate Effluent Regulations
pH, s. u. 6.5 - 9.0 c/ Water Qualiry Standards
Chronic WET Testing Report Statistical Difference c/ State Discharge Permit Regulations
Potentially Dissolved Aluminum, mg/! 0.087 / 4.5 b/ Antidegradation-Based /WQS-Based
Total Arsenic, rng/I Report / 0.050 b/ Antidegradation-Based Lirnit
Potentialy Dissolved Cadmium, mg/l 0.00099 / 0.037 b/ Antidegradation-Based /WQS-Based
Potentially Dissolved Copper, mg/1 0.0/0 / 0.07! b/ Antidegradation-Based /WQS-Based
Dissolved Iron, mg/l 0.30 /Report b/ Antidegradation-Based Limit
Total Recoverable Iron, mg/1 1.0 /Report b/ Antidegradation-Based Limit
Potentially Dissolved Lead, rng/l 0.0025 / 0.29 b/ Antidegradation-Based /WQS-Based
Dissolved Manganese, mg/[ 0.050 /Report b/ Antidegradation-Based Limit
Total Recoverable Manganese, rng/1 3.0 /Report b/ Antidegradation-Based Limit
Total Radium 226+228, pCi/1 Report / 5.0 b/ Antidegradation-Based Limit
Total Selenium, mg/! Report / 0.0095 b/ Antidegradation-Based Limit
Potentially Dissolved Silver, mg/l 0.000030 / 0.0054 b/ Antidegradation-Based /WQS-Based
Tota( Natural Uranium, rng/l 0.92 / 9.3 b/ Antidegradation-Based /WQS-Based
Potentially Dissolved Zinc, mg/l 0.098 / 0.49 b/ Antidegradation-Based /WQS-Based
Total Fluoride, mg/l Report / 4.7 b/ Antidegradation-Based Limit
Total Sulfate, rng/l 550 /Report b/ Antidegradation-Based Limit
a/ 34Day Average c/ Mininnmr-Marimum e/ 34Day Average/7-Day Average
b/ 30.Day Average/Daily Marimum d/Daily Marimum
j/ For every outtall with oil and grease monitoring, in the event an oi(sheen or floating oil is observed, a grub sample shall be collected,
awlyzed, and reported on the appropriate Discharge Monitoring Report (OMR). br addition, corrective action slmll 6e mken immediately m
mitigate the discharge ojoil mrd grease. A description of the corrective action taken should be included with the DMR.
2. Description ojDischarAe Point 002:
Discharge Point 002 corresponds m the seepage front tlmt developed as a result oJUte historic Jlow of groundwater
from the backjilled West Pit into the adjacent Rito Seco alluvial aquifer within the region of the window.
The Jlow of groundwater from the backfi[led West Pit will continue to be eliminated through dte implementation of a
limitation relating to the graundwa[er elevation depth for well BF-4 at 8583 ft. oast, a BMP comprised of establishing
a hydrardic gradient reversal between the West Pit and the adjacent Rito Seco alluvial aquifer, and a compliance
schedule for 002, as is included in Pan /.A.S. ojthe permit, A derailed Hydrologic characterization of groundwater
flows in the vicinity of the West Pit x~as conducted as part of the response actions implemented by BMRI/BMG under
the OMG penrtir. Results obtained from the Hydrologic characterization supported an interpretation that the flow of