HYDRO23023

• Permit No: C1981020
• IBM Index Class Name: Hydrology
• Doc Date: 4/22/1991
• Doc Name: RATIONALE FOR PUBLIC NOTICE
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

' COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division
Rationale - Page 5. Permit No. CO-0040827.
VI. TERMS AND CONDITIONS OF PERMIT
Table VI-2 -- Effluent Limits - 002
Parameter
Limit
Rationale
Flow, MGD Report a/
TSS, mg/1 35/70 b/
Total Iron, mg/1 3.0/6.0 b/
pH, s.u. 6.5-9.0 c/
Oil and Grease, mg/1 10 d/
Total Dissolved Solids, mg/1 Report 3/
Whole Effluent Toxicity, Acute Report
NA
New Source Performance Stds
New Source Performance Stds
Water Quality Standards
State Effluent Regulations
Salinity Regulations
See Discussion
a/ 30 Day Average
b/ Average of daily values for 30 consecutive days/Daily maximum
c/ Minimum-Maximum
d/ Daily Maximum
1. Water Quality Standard Based Effluent Limitations:
a) pH: For pH, the limits are set directly from stream standards.
2. Applicable Federal Effluent Guidelines and Standards: The federal
gu a Ines w c app y to t is type o .foci i±y are found under 40
CFR 434, the Coal Mining Point Source Category. The limitations
which apply are:
Table VI-3 -- Federal Standards
Parameter
Total Suspended Solids, mg/1
Total Iron, mg/1
Settleable Solids, ml/1
35
3.0
NA
Daily Maximum
70
6.0
0.5
The above federal limits are from Subpart D of 40 CFR 434, Alkaline
Mine Drainage, New Source Performance Standards (434.45) and
Subpart F, Miscellaneous Provisions, Effluent Limitations for
Precipitation Events (434.63).
The limits used are for new sources. The definition of a new
source includes "discharge into a drainage area not previously
affected by wastewater discharge from the mine." Since no
discharge has been reported from the mine area so far, any
discharge in the future can be considered a new source.
Avg, of Daily Values
Eor 30 Consecutive Days