PERMFILE107381

• Permit No: C1994082A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: NPDES PERMIT YOAST MINE
• Section_Exhibit Name: TAB 15 APPENDIX 15-1
• Media Type: D
• Archive: Yes

•
B. MONITORING REQUIREMENTS
Storm Exemption - 009
PART I
Page lg of 19
Permit No. CO-0000221
If the permittee intends to use the 10-year, 2a-hour storm exemption, a report
must be submitted within 90 days after the effective date of this permit,
documenting that the facility is designed, constructed and will be maintained to
contain or treat:
(a) The maximum volume of wastewater which would be generated by the facility
during a 24-hour period without an increase in volume from precipitation; and
(b) The maximum volume of wastewater resulting from a 10-year, 24-hour
precipitation event, including the volume which would result from all areas
contributing runoff to the individual treatment facility (i.e., all runoff
not diverted from the active mining area or the mill area).
In addition, if discharge occurs as a result of the 10-year, 29-hour storm volume
being exceeded and the permittee wishes to claim an exemption from technology
based effluent limitations, the permittee shall submit, within 5 days of the said
discharge, documentation that the facilities were maintained to contain or treat
the previously specified volumes. The permittee must also submit documentation
of the storm event, including the precipitation recorded at the closest official
precipitation gauge station (or the permittee's own gauge), the volume of storm
runoff produced and the steps taken to maintain treatment and minimize the amount
of overflow.
• All data/documentation required by this section which can not be reported on
applicable discharge monitoring report forms (DNB's) shall be reported in lecter
form as an attachment to the DMR. Submittal of documentation of containment,
maintenance and precipitation records above does not exempt the permittee from the
notification requirements of PART II.A.3. of this permit.
Chronic WET Testing - Outfalls 004 and 008
a.) Testing and Reportin4 Reguiremente
Tests shall be done at the frequencies listed in Parts I.B.l.a and I.B.l.b.
Test results shall be reported along with the Discharge Monitoring Report
(DMR) submitted for the reporting period during which the sample was taken.
(i.e., WET testing results for the first calendar quarter ending March 31
shall be reported with the DMR due April 28.) The results shall be submitted
on the Chronic Toxicity Test report form, available from the Division.
Copies of these reports are to be submitted to both the Division and EPA
along with the DMR.
The permittee shall conduct each chronic WET test in general accordance with
methods described Short Term Methods for Estimating the Chronic Toxicitv of
Effluents and Receiving Waters to Freshwater Organisms, EPA/600/4-89/001 or
most current editions, except as modified by the most current Division
guidance document entitled Guidelines for Conducting Whole Effluent Toxicitv
Testa. The permittee shall conduct such tests using both Ceriodaphnia dubia
and fathead minnows.
Amended ~q,7 0 94 Effective 09/01/94
Amended J U1~ ~GQ~ - Effective ~~pp~