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COLORADO DEPARTMENT OF PUBLIC HEALTH AND ENVIRONMENT, Water Quality Control Division
<br />Rationale, Page 2, COG-0500000 Sand and Gravel General Permit
<br />Groundwater - Under Section 25-8-202(7) of the Colorado Water Quality Control Act, sand and gravel discharges to groundwater can not
<br />be authorized under the Division's jurisdiction, and a certification to discharge can not be issued. In these instances, an applicant will need
<br />to contact the Division of Reclamation Mining and Safety, or the Environmental Protection Agency under the Underground Injection
<br />Control program. In some cases, where the discharge to groundwater is in the alluvial material, and the groundwater discharge is
<br />considered to impact the surface waters, a facility may be authorized under this general permit.
<br />Stormwater -When stormwater mixes with process water, the process water limitations (Part LB of the permit) apply to the discharge of
<br />that mixed water. The stormwater section (Part 1. C of the permit) is intended to cover those portions of a nonmetallic minerals
<br />production operation (except fuel) that are not already subject to effluent limitations under 40 CFR 436, and to cover stormwater runoff
<br />from asphalt and concrete batch plants and recycling areas.
<br />Domestic Wastewater - Note that this general permit does not cover the discharge of domestic type wastewater. If this type of coverage
<br />is needed, the permittee may apply for an individual permit, or may apply separately for a domestic general permit (if applicable).
<br />Need for an Individual Permit- Dischargers that do not fit under this characterization, possess highly toxic chemicals in elevated
<br />concentrations, elect to have an individual permit, or wish to have mixing zone or site-specific antidegradation considerations, should
<br />apply for coverage under an individual permit.
<br />B. Application
<br />Dischargers can apply for coverage under this general permit once the permit is issued. Holders of certifications under the administratively
<br />extended Sand and Gravel and other Nonmetallic Mineral Mining Permit (COG-0500000) will automatically be transferred to this new
<br />general permit. Their coverage will be transferred to the new general permit without a lapse of coverage (i. a discharging without a permit)
<br />and without loss of fee payments. Incidentally, the annual fee for each of these general permits is $270, effective July 1, 2007. The permittee
<br />will have 90 days, from the date of transfer, to comply with any new terms and conditions of this general permit. For all others, the owner
<br />or operator of the site shall submit one original completed application and a copy, including a signed certification that the SWMP is
<br />complete at least thirty days prior to the commencement of mining activities.
<br />III. EFFLUENT LIMITATIONS
<br />Numeric effluent limitations are imposed for pollutants that are specific to the discharges covered, and are shown in Tables IF-1 through
<br />III-6. Some of these limits are based on the EPA Federal Effluent Guidelines for the applicable point source category and are described
<br />below. The certification will state which conditions apply, based on the nature of the discharge. Note that any parameter that is
<br />determined to be a site-specific pollutant of concern may be added to the discharge certification.
<br />Table HI-1- crushed stone (subpart B), construction sand and gravel (subpart C), and all other industrial facilities covered under
<br />SIC Code 14. extent those specifically lictod in the inhtae halms.
<br />Effluent Parameter Discharge Limitations Rationale
<br /> 30 Da Av 7 D Av Dail Max
<br />Flow, m d Report NA Report Dischar a Evaluation
<br />Total Suspended Solids, m g17 30 45 NA State Effluent Regulations
<br />H, s.u. NA NA 6.5-9.0 Water ali Standards
<br />Oil and Grease, m /1 NA NA 10 State Effluent Regulations
<br />Site specific
<br />Selenium, u /1 Various NA Various Water uli Standards
<br />Metals, u g17 Various NA Various Water Quality Standards
<br />Organics, u R Various NA Various Water uali Standards
<br />Whole E uent Toxicity
<br />Chronic Stat. Di & IC25>IWC State Permit Limitations
<br />Acute LC50> 100% State Permit Limitations
<br />Total Dissolved Solids, in /1 Report NA Report Salinity Regulations
<br />Total Phosphorus, m /1
<br />1, A Report NA
<br />--d 0.2-1.0 Control Regulations
<br />.,,,..? ...,, uv,.,,auy app y ,o discharges wimin the Colorado River 13asm.
<br />??The Phosphorus limitations apply to discharges to the Dillon Reservoir Watershed, Cherry Creek Reservoir Watershed, Chatfield Reservoir
<br />Watershed, and the Bear Creek Watershed, as defined in Regulation 71, 72, 73, or 74, respectively.
<br />.. Not applicable to every certification. If included in the permit, either acute or chronic will apply. See Section IV (g)
<br />0-0
<br />Selenium will be included based on the presence of selenium-containing shale deposits
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