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

• Permit No: M2009076
• IBM Index Class Name: PERMIT FILE
• Doc Date: 9/25/2009
• Doc Name: EPA Superfund Record of Decision
• From: Venture Resources
• To: DRMS
• Media Type: D
• Archive: No

EXTENSION OF THE LOT BACK TO THE QUARTZ HILL TAILINGS TO RECOVER LOST PARKING SPACES. THE STATE
ALSO RECOMMENDS THAT EPA CONSIDER PAVING THE PARKING SURFACE AND SEALING THE SIDE-SLOPES BECAUSE
OF THE DISTRICT-WIDE SIGNIFICANCE OF THIS PILE.
'S RESPONSE: EPA HAS STUDIED THE ACTIVE EROSION AT THE PARKING LOTS. AS RECOMMENDED BY CDH,
S AND DITCHES WILL BE CONSTRUCTED FOR RUNON CONTROL. RUNOFF CHANNELS WILL ALSO BE
STABILIZED. DETAILED DESIGNS WILL BE PROVIDED DURING THE REMEDIAL DESIGN.
DETAILED DESIGNS WILL BE PROVIDED DURING THE REMEDIAL DESIGN. PAVING IS CURRENTLY NOT PLANNED,
BECAUSE ANALYSIS SHOWED THERE ARE NO POTENTIAL HUMAN HEALTH EFFECTS FROM INHALATION OF BLOWING
DUST AT THE PARKING LOTS. EPA ACKNOWLEDGES CDH'S PLANS TO EVALUATE IMPACTS DUE TO BLOWING DUST
FROM THE PARKING LOTS.
COMMENT: CDH COMMENTED THAT THE USE OF SOIL COVER (CAPPING) AS A REMEDIAL TECHNIQUE WAS
DISCARDED TOO EARLY IN THE SCREENING PROCESS. CDH BELIEVES THAT, IN CONTRAST TO THE STATEMENT
IN THE FS REPORT ON PAGE 2-61, THE SOIL CAP MAY HAVE SUFFICIENT STORAGE CAPACITY TO REDUCE
PERCOLATION OF WATER INTO THE WASTE SIGNIFICANTLY. IN GENERAL, THE STATE RECOMMENDS
RECONSIDERATION OF SOIL COVER AND/OR REVEGETATION AS A VIABLE LEACHATE AND EROSION CONTROL
TECHNOLOGY.
EPA'S RESPONSE: EPA HAS CONCLUDED THAT GENERATION OF LEACHATE DUE TO INFILTRATION IS NOT A
PROBLEM, AND THEREFORE, A COVER OR SOIL CAP IS NOT NEEDED FOR LEACHATE CONTROL. REGARDING
EROSION CONTROL, RUNOFF DUE TO DIRECT PRECIPITATION ON THE SURFACE IS A RELATIVELY MINOR SOURCE
OF CONTAMINATION VERSUS RUNON TO THE TAILINGS AND WASTE ROCK PILES. THEREFORE, EVEN THOUGH A
SOIL CAP CAN BE EFFECTIVE IN PREVENTING EROSION, EPA HAS DETERMINED THAT IT WOULD BE
SIGNIFICANTLY LESS COST-EFFECTIVE THAN USE OF THE PREFERRED RUNON CONTROLS IN PREVENTING
EROSION.
COMMENT: WITH REGARD TO NEUTRALIZATION AGENTS (FS REPORT, PAGE 2-83), CDH COMMENTED THAT NO
DISCUSSION IS GIVEN TO THE VOLUME OF NEUTRALIZING AGENT THAT WOULD BE NEEDED. THE STATE BELIEVES
T IT IS POSSIBLE THAT THE VOLUME OF KILN DUST NEEDED WOULD NEGATIVELY IMPACT THE PROJECT TO
EXTENT THAT USE OF THE NEXT. MOST INEXPENSIVE AGENT (COMMERCIAL LIME) MAY BE WARRANTED.
EPA'S RESPONSE: IN EVALUATING THE PROPOSED ALTERNATIVES, EPA CONSIDERED FIXATION OF ONLY THE
UPPER 18 INCHES OF WASTE MATERIAL. GIVEN THIS LIMITED DEPTH OF FIXATION, THE VOLUME INCREASE
(EVEN THOUGH SIGNIFICANT ON A SMALL SCALE) IS NOT A CONCERN. FOR EXAMPLE, EVEN A VOLUME
INCREASE OF 50 PERCENT WOULD ADD ONLY NINE INCHES TO THE TOP OF THE PILE.
COMMENT: THE STATE RECOMMENDS THAT THE DIVERSION DITCHES THAT WILL BE USED TO CONTROL RUNON AT
THE SITE BE LINED WITH SOMETHING LESS COSTLY THAN CONCRETE. THE STATE BELIEVES THAT DITCHES
SHOULD BE CONSTRUCTED IN UNDISTURBED GROUND IF POSSIBLE TO MINIMIZE CONTACT WITH WASTE. THE
STATE ALSO SAYS THAT AN OPERATION AND MAINTENANCE (0 AND M) COMPONENT SHOULD BE ADDED TO THE
COST ESTIMATE.
EPA'S RESPONSE: EPA HAS RE-EVALUATED THE LINING MATERIAL FOR THE DITCHES AND CURRENTLY BELIEVES
THAT SOIL CEMENT MAY BE A MORE COST-EFFECTIVE OPTION. CDH'S OTHER RECOMMENDATIONS WILL BE
EVALUATED IN THE REMEDIAL DESIGN PHASE. 0 AND M COSTS HAVE BEEN ADDED TO THE COST ESTIMATE AND
ARE PROVIDED IN TABLE 3 OF THE ROD.
COMMENT: CDH NOTED SEVERAL TYPOGRAPHICAL ERRORS IN THE FS REPORT.
EPA'S RESPONSE: EPA APPRECIATES THE COMMENT; THESE ERRORS WILL BE CORRECTED.
3. GOVERNMENT AND SUPERFUND PROCEDURES AND ACTIVITIES
COMMENT: A MINING ENGINEER AND REPRESENTATIVE OF A LOCAL MINING ORGANIZATION ASKED WHAT WEIGHT
COMMUNITY COMMENTS HAVE IN THE SELECTION OF THE FINAL ALTERNATIVE AND IN EPA'S DECISIONS ABOUT
4v CLEAR CREEK/CENTRAL CITY SITE.
EPA'S RESPONSE: UNDER THE SUPERFUND PROGRAM, CONGRESS REQUIRES EPA TO CONSIDER COMMUNITY
COMMENTS ALONG WITH EIGHT OTHER CRITERIA IN MAKING A FINAL SELECTION OF REMEDIES. AT THE CLEAR
CREEK/CENTRAL CITY SITE, EPA HAS MODIFIED ITS ORIGINAL PLANS AND IS CURRENTLY CONSIDERING
SEVERAL ADDITIONAL CHANGES, BASED ON PUBLIC COMMENTS. SUPERFUND REQUIREMENTS DICTATE, HOWEVER,