HYDRO20590

• Permit No: C1981014
• IBM Index Class Name: Hydrology
• Doc Date: 4/23/1991
• Doc Name: FINAL PERMIT COLO WASTEWATER DISCHARGE PERMIT SYSTEM CO-0036595 ENERGY FUELS COAL INC
• From: CDOH
• To: RANDY ACRE
• Permit Index Doc Type: CORRESPONDENCE
• Media Type: D
• Archive: No

COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division
Rationale - Page 7. Permit No. CO-0036595.
( VI. TERMS AND CONDITIONS OF PERMIT
The above federal limits are from Subpart D of 40 CFR 434, Alkaline
Mine Drainage, -est Available Technology (434.43), and Subpar[ F,
Miscellaneous Provisions, Effluent Limitations for Precipitation
Events (434.G3).
a) Active Mining:
The only limitations which are applicable for discharge points
004 and 005 are indicated in Table VI-2. -ecause these points
include mine drainage, the discharges are not eligible for the
storm event exemption conditions under active mining
requirements.
The following discussion is applicable for discharge points 001
and 002.
Limitations for pH and oil and grease apply to all discharges,
regardless of precipitation conditions. Additionally, TSS and
total iron samples should always be taken. If the results of..
the analyses exceed the permit limit, the permittee may submit
documentation proving that the discharge was precipitation
induced. The proof of the size of the precipitation event
consists of:
(i) rain gauge data or the volume of water contained in the
snow, based upon calculations from actual snow samples;
(ii) the sample results For TSS, iron, pH, settleable solids and
oil and grease; and
(iii) influent/effluent metered flow.
It is only upon acceptance by the Division of said proof that
the settleable solids limitation will apply in place of the TSS
and total iron limitations for precipitation events that are
less 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 stopped.
For snowmelt, the Division allows these exemptions for a period
up to 48 hours after inflow to the sedimentation pond has ceased,