2009-09-25_PERMIT FILE - M2009076 (42)

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COLORADO MINED LAND ACT AND PROHIBITION OF WASTE DISPOSAL IN GROUND WATER (GREGORY TAILINGS), AS THEY WILL NOT BE MET UNDER THE REMEDIATION. DISCHARGE STANDARDS UNDER COLORADO 40 CFR 440 ARE RELEVANT AND APPROPRIATE BASED ON PAST ACTIVITY ON THE SITE. RESOURCE CONSERVATION AND RECOVERY ACT (RCRA) ARARS ARE NOT RELEVANT BECAUSE OF THE MINERAL WASTE EXCLUSION AND BECAUSE TESTING WED THEM TO BE NONHAZARDOUS. THE WORDING IN PARAGRAPH 5, PAGE 2-28 OF THE DRAFT FS REPORT, RE IT IS STATED THAT FEDERAL WATER QUALITY CRITERIA (WQC) FOR CERTAIN PARAMETERS ARE RELEVANT, SHOULD BE CHANGED TO SAY THAT WQC ARE RELEVANT, WITH ONLY THE SPECIFICALLY NOTED PARAMETERS IDENTIFIED AS EXCEEDING THE CRITERIA. AS NOTED ABOVE, CDH BELIEVES THAT ARARS SHOULD BE RELATED TO THE OVERALL REMEDY RATHER THAN JUST THE FIVE PILES THAT NOW CONSTITUTE THE SITE. EPA'S RESPONSE: EPA WILL INCORPORATE CDH'S SUGGESTIONS CONCERNING THE WQC PARAMETERS EXCEEDING THE CRITERIA. EPA'S PREFERRED REMEDY FOR THE FIVE PILES IS AN INTERIM MEASURE. EPA WILL CONTINUE TO EVALUATE THESE ARARS AS PART OF THE OVERALL REMEDY FOR THE SITE. FOR EXAMPLE, COLORADO 40 CFR 440 WILL BE CONSIDERED IN THE DESIGNS OF OPERABLE UNITS ONE AND THREE. 2. STUDY METHODS AND FINDINGS COMMENT: THE CITY ADMINISTRATOR OF CENTRAL CITY, RESPONDING ON BEHALF OF THE CITY COUNCIL TO EPA'S REQUEST FOR PUBLIC COMMENT, EXPRESSED CONCERN ABOUT THE POSSIBLE IMPACTS OF EPA'S PREFERRED CLEANUP ALTERNATIVE ON THE COMMUNITY'S BUSINESSES. IN REFERENCE TO CONTROLLING RUNON TO THE PARKING AREA NEAR THE QUARTZ HILL SITE BY BUILDING DITCHES TO DIVERT WATER AROUND THE PARKING LOTS, THE CITY ADMINISTRATOR NOTED THAT EVEN THE PRESENCE OF CONSTRUCTION EQUIPMENT COULD BE DETRIMENTAL TO THE BUSINESSES BECAUSE OF THE CONFUSION AND NOISE THAT POTENTIAL CUSTOMERS MIGHT FIND INTIMIDATING. THE CITY ADMINISTRATOR BELIEVES THAT CLOSURE OF THE LOTS, EVEN TEMPORARILY, COULD CAUSE SERIOUS PROBLEMS. CONSTRUCTION DURING THE 90-DAY PEAK BUSINESS SEASON WOULD BE MOST DETRIMENTAL TO THE BUSINESSES ACCORDING TO THE CITY ADMINISTRATOR. HE IS ALSO CONCERNED ABOUT THE EFFECT OF THE DITCHES ON ENTRANCES AND EXITS. IN ADDITION, HE IS CONCERNED ABOUT THE LOSS OF PARKING SPACES IN THE LOTS IF EFFORTS TO STABILIZE THE SLOPES REDUCE THE SIZE OF THE LOTS. HE NOTED THAT ASPHALT CAPPING, IF CAPPING IS PART OF THE SOLUTION, COULD ENHANCE THE PARKING LOTS AND WOULD BE BENEFICIAL TO THE COMMUNITY. THE CITY ADMINISTRATOR ASKED T EPA PROVIDE THE CITY WITH ANY PLANS OR DRAWINGS THAT WOULD AFFECT THE PARKING LOTS. EPA'S RESPONSE: EPA WILL CONSIDER THESE ISSUES DURING REMEDIAL DESIGN AND WILL CONSULT WITH THE CITY DURING THIS PROCESS. COMMENT: THE CITY ADMINISTRATOR OF CENTRAL CITY ALSO QUESTIONED WHETHER THE RUNON CONTROL SYSTEM WOULD HAVE AN EFFECT ON THE CITY'S DRAINAGE SYSTEM. HE ASKED WHERE RUNON WATER WOULD BE DIVERTED AND WHETHER THE CHANGES CREATED BY THE RUNON SOLUTION COULD CREATE ADDITIONAL RISKS OF FLOOD HAZARD FOR THE CITY. THE CITY IS SEEKING COMMUNITY DEVELOPMENT BLOCK GRANT FUNDS TO RESOLVE CONCERNS IDENTIFIED IN ITS FLOOD HAZARD REPORT. HE ASKED WHETHER EPA'S EFFORTS TO CONTROL RUNON AND THE CITY'S EFFORTS TO CONTROL STORMWATER DRAINAGE COULD BE MUTUALLY BENEFICIAL. HE REQUESTED THAT THE CITY BE KEPT INFORMED OF EPA'S INTENTIONS SO THAT THE CITY AND EPA CAN COORDINATE FUTURE EFFORTS. EPA'S RESPONSE: EPA WILL CONSIDER THE EFFECT OF DIVERTED RUNON WATER ON THE CITY'S DRAINAGE SYSTEM DURING REMEDIAL DESIGN. EPA WILL CONSULT WITH THE CITY DURING REMEDIAL DESIGN AND WILL KEEP THE CITY INFORMED OF PLANS THAT MAY AFFECT THE CITY'S STORMWATER DRAINAGE SYSTEM. COMMENT: A MINING ENGINEER COMMENTED THAT THE FS FINDING THAT SLOPES AT THE SITE ARE UNSTABLE CONTRADICTS COMMON SENSE AND GOOD ENGINEERING PRACTICE. HE SAID THAT THE FACT THAT THE SLOPES HAVE STOOD IN PLACE FOR OVER EIGHTY YEARS, AND PROBABLY HAVE BEEN SUBJECT TO SOME MEASURE OF FLOODING DURING THAT TIME, ARE INDICATIVE OF THEIR STABILITY. THE MAYOR OF IDAHO SPRINGS ALSO COMMENTED THAT THE MINE DUMPS ARE MORE STABLE THAN MOST SOILS BECAUSE OF A CEMENTING ACTION THAT TAKES PLACE IN THE TAILINGS PILES, AND REQUESTED THAT THIS CEMENTING ACTION BE DISCUSSED IN THE FS REPORT. ANOTHER COMMENTER INDICATED THAT, BECAUSE OF THE LENGTH OF TIME THE TAILINGS HAVE BEEN IN PLACE, HE DOES NOT BELIEVE THAT THERE ARE ANY PARTICULAR TIME PRESSURES FOR REMOVAL OF THE TAILINGS. IA'S RESPONSE: THE STABILITY OF THE WASTE ROCK AT THE BIG FIVE WAS EVALUATED USING ACCEPTED GEOTECHNICAL TECHNIQUES. THE "CEMENTING" OF THE MATERIAL WAS CONSIDERED IN THE EVALUATION. AFTER FURTHER REVIEW OF THE EVALUATIONS AND SITE INSPECTIONS, EPA BELIEVES THE CONCLUSIONS ARE CORRECT. IT SHOULD BE NOTED THAT SINCE CLEAR CREEK WAS RE-ROUTED DUE TO THE CONSTRUCTION OF INTERSTATE HIGHWAY 70, THE RIVER CHANNEL HAS BEEN NARROWED AND HAS UNDERCUT THE TOE OF THE WASTE