HYDRO27094

• Permit No: C1982056
• IBM Index Class Name: Hydrology
• Doc Name: PART I PAGE 1B OF 19 PN CO-0036684
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

•ii ii iiii iii iiiiu iii •
999
PART I
• Page lb of 19
Permit No.: CO-0036684
A. TERMS AND CONDITIONS (Continued)
c) Effective during periods of precipitation greater than the 10-year,
24-hour event for this facility.
Any discharge or increase in volume of a discharge caused by
precipitation within any 24-hour period greater than the 10-year,
24-hour precipitation event (or series of storms or snowmelt of
equivalent volume) may comply with the following limitations instead of
the limitations of item a) and b) immediately preceeding.
Flow - (MGD) - monitoring only per Part I.B.1.
Electrical Conductivity, micromhos/cm - monitoring only per Part I.B.1.
pH - (Standard Units) shall remain between 6.5 and 9.0 c/.
011 and grease shall not eaceed 10 mg/1 c/ in nay grab sample nor shall
there be a visible sheen.
d) Additional conditions-effective at all times.
There shall be no discharge of floating solids or visible foam in other
than trace amounts. The discharge shall not contain any sanitary
• sewage or other pollutants not associated with active mining operations.
2. Requirements for Effluent Limitation Compliance Determination
The permittee shall have the burden of proof that a discharge was
caused by a precipitation event in order to qualify for the alternate
limitations in Part I.A.l.b or I.A.l.c. In the absence of satisfactory
proof, the limitations in Part I.A.l.a shall prevail. Monitoring of
all effluent parameters shall be required as per I.B.1, regardless of
the cause of the discharge.
3. Post-Mining Areas
Commencing at the time active mining has ceased and surface areas have
been returned to the required contour, all applicable discharges shall
be subject to limitations other than those specified in Part I.A.1.
These post-mining limitations shall remain in effect until bond
release. The permittee shall notify the Division upon cessation of
active mining so that appropriate permit modifications can be made.
See Part I.C. for Footnotes
Amended 03/26/85
• Amended q~~p~gn Effective a~~~in~
Code: 1 - 8 Date: 9 - 84