2005-12-02_PERMIT FILE - C1981019

Home Browse Search

COLORADO DEPARTMENT OF PUBLIC HEALTH & ENVIRONMENT -Water Quality Comrol Division Rationale -Page 11 Permit No. COR-040000 • VII. CHANGES AFTER PUBLIC NOTICE (cons.) stormwater discharges associated with mining activity stilt occur, the owner or operator is still responsible for the cominued (albeit reduced) delivery of pollutants to the stream. - 2. The differentiation between stormwarer and process water at a mine or milt site. One commenter requuted that the Rationale be expanded to make clear-which sources of water at a mine site are srormwater (covered by this permit) and which sources are process waxer" (not covered by this permit). Response: "Process water" is a tam ustd by the Division to refer to waters which when discharged, are required to have conventional permits with numeric effluem limits. Thee include wastewaters that were generated or used in an industrial procus, or demerit wastewater. They also include mine drainage and many other source of water from specific industrial categoric that are defined and set forth in federal regulation (40 CFR subchapter N). Several source of predpitarion-induced runoff from active mine sites are included in the 40 CFR, subchapter N, pan 440, Ej(btent Limitation Guideline. The confusion 6e[wern storntwater artd procus water at mine sites arises because the regulatory definitions overlap somcwhat. Curremly, this overlap is addrused in a Division Polity documeu "Definition of Process Water and Stormwater at Non-Coal Mining Sires (policy number WQP-17).' Since this overlap in definitions is also a subject of current national litigation, the Division believes that the polity document is the appropriate place for the lengthy discussion. This policy is available jrom the Division. 3. Exemptions from pnmittine or termination criteria: ti • Scveral commenters requeted that exemption of one kind or another be included in the general permit. Two commemors questioned the assertion that stormwater discharges jrom inactive mines contribute to water quality problems, specifically in San Juan County. A few commenters asked for an exclusion from permit requirernems if it can be demonstrated that the exposed material would not be expected to degrade water quality. One commrntor requested aemption from permit requirements if the mine has been inactive since 1973 and the site is [us than 2 acre, Response: Essentially, the Division is unable to gram exemptions to permitting requirements in a permit document. The federal and state rules (40 CFR 722.26 and S CCR 1002-2, § 6.4.2, respectively) set out which circumstances and which activirie require permit coverage. Permits are lower in the regulatory hierarchy than rule, and cannot grant an aemption which is in conflict with rules. Exemptions would require a rules change at both the federal and state levels, as the state rule primarily repeats the federal rule. Change in the state rule alone is limited to being no less stringent than federal rules. Reeardine the stormwater contributions to water aualiri problems in San Juan County: Comrary to the assertion that there is no evidence that stormwater discharges from mine workings contribute to the water quality problems in San Juan County, information supports the conclusion that thce sources are significant. Analysis of water quality data in the Upper Animas River basin by the Division had shown that precipitation- induced runoff from inactive mine/mill sites is a sigrificam pan of the zinc loading in the Animas River. The coraribwion from these San Juan County situ appears to 6e most acute during the early spring snow-melt flush. The data were grnerated by monitoring water quality above and below individual situ, as well as extensive data collected by the Colorado River Watch Program on Cemem Creek, Mincral Creek and the Upper Animas Rivcr. In addition, an unpublished PhD dissertation concluded that the majority of zinc loading in the Cemrnr Creek watershed is comributed by old mine waste dumps (Caruso, l995), Cement Creek has no aquatic life due in pan to the toxic levels of zinc. • Reeardine an exemption for uncontaminated stormwater.• The regulations state that permits are required for: "...mining operations....that discharge stormwara contaminated by contact with or that has come into contact with, any overburden, raw material, intermediate products, finished products, byproducts or waste products located on the site... (S CCR 1002-2 § 6.4.2(5)(c)(iii)) (emphasis added). However, after further