PERMFILE106134

• Permit No: C1982057A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: NPDES PERMIT
• Section_Exhibit Name: TAB 15 APPENDIX 15-4 PART 2
• Media Type: D
• Archive: Yes

COLORADO DEPARTMENT OF HEALTH, Water Quality Cont ro! Division
Rationale - Paqe 9. Permit No. CO-0000221.
~I. TERMS AND CONDITIONS OF PERMIT
iron limitations for precipitation events that are lees than or equal to
the 10-year, 24-hour storm event. Failure to submit such proof will
result in the Division disallowing the exemption.
Similarly, for precipitation events greater than the 10-year, 24-hour
event (or equivalent snowmelt volume), proof of the size of the storm
will consist, again, of (i)-(iii), above. Upon acceptance of proof that
discharge was caused by precipitation, compliance with TSS, total iron
and settleable solids limitations will be exempted. This means such a
discharge would be subject to pH and oil and grease limitations only for
the exempted timeframe, The Division allows these exemptions for a
period of to 48 hours after measurable rainfall has stepped. For
snowmelt, the Division allows these exemptions for a period up to 48
hours after inflow to the sedimentation pond has ceased.
b) Post-Mining Areas - 009, 010: Commencing at the time active mining has
ceased and surface areas have been returned to the required contour and
the permit has been modified, all applicable discharges shall 6e subject
to limitations other than those specified in Part I.A.L. 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.
• 3. Reoulations for Effluent Limitations: The Regulations for Effluent
Limitations (10.1.0), apply to the conventional pollutants. For this
facility the limitation for Oil and Grease is based on this regulation.
4. Discussion of Limitations;
a) Salinity (Total Dissolved Solids The Regulation for Implementation of
the Colorado Salinity Standards Through the Colorado Discharge Permit
Program (3.10.0), addresses the discharge of total dissolved solids
(TDS) to the Colorado River Basin. It is a requirement of this
regulation that all discharges into the Colorado River basin be
monitored for TDS on a continual basis. Therefore, in compliance with
this regulation the permittee must monitor for TDS on a quarterly basis
at existing discharge points 002, 003, 004, 006 and 008.
Discharge points 005, 009 and 010 are new sources. The regulation
provides more detailed guidance on the application of salinity standards
developed pursuant to Section 204 of the Colorado water Quality Control
Act. The objective of the regulation is to have, whenever practicable,
a no-salt return policy for industrial discharges.
The regulation provides for a waiver from the no-salt discharge
requirement when the salt load reaching the Colorado River is less than
one ton per day or 350 tons per year, whichever is less.
Ponds which only treat surface runoff are expected to discharge on an
intermittent basis, and so be more likely to meet the one ton/day Limit.
For 009 and 010, TDS shall be sampled on a monthly basis until aiz
samples have been analyzed. A report of "No Discharge" shall not be
counted as one of the six samples. Thereaote[, monito[ing shall
continue on a quarterly basis.