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

WERE MORE FEASIBLE THAN SYNTHETIC LINERS FOR NON-AUTO TRAFFIC AREAS. SELECTION OF SOIL CEMENT
COVERS WOULD ALSO PROBABLY BE PREFERRED BY THE COLORADO HISTORICAL SOCIETY OVER A LINER. THE
MOST FEASIBLE CAPPING ALTERNATIVE FOR THE PARKING LOTS IS PAVING.
0 ALL CASES DISCUSSED ABOVE, RUNON AND RUNOFF CONTROL WOULD BE PROVIDED. THIS WOULD CONSIST OF
TCHES UPGRADIENT OF THE CAPPED AREA TO DIVERT WATER AND DITCHES OR CULVERTS BELOW THE SITES TO
DIVERT RUNOFF. CAPPING OF THE TAILINGS AND WASTE ROCK PILES WOULD BE A PERMANENT SOLUTION THAT
REMOVES EXPOSURE TO HUMAN HEALTH AND THE ENVIRONMENT.
OFF-SITE DISPOSAL: UNDER THE OFF-SITE DISPOSAL ALTERNATIVE, TAILINGS AND WASTE ROCK PILES WOULD
BE EXCAVATED AND TRANSPORTED FOR DISPOSAL AT A MUNICIPAL LANDFILL SITE SUCH AS THE LANDFILL
OPERATED BY BFI AT 88TH AND TOWER ROAD NORTHWEST OF DENVER. LEACHATE TESTS INDICATE THAT THE
TAILINGS AND WASTE ROCK ARE NOT RCRA CHARACTERISTIC WASTE AND THEREFORE DO NOT HAVE TO BE SENT
TO A RCRA LANDFILL.
REMOVAL OF THE TAILINGS AND WASTE ROCK PILES IS A PERMANENT SOLUTION THAT REMOVES EXPOSURE TO
HUMAN HEALTH AND THE ENVIRONMENT. DUST CONTROL MEASURES MUST BE IMPLEMENTED DURING EXCAVATION
AND TRUCKS WOULD HAVE TO BE LINED AND COVERED DURING TRANSPORTATION.
CHEMICAL FIXATION: IN THE INITIAL SCREENING PROCESS, KILN DUST AND THREE PROPRIETARY MATERIALS
WERE SELECTED FOR DETAILED EVALUATION. WASTE ROCK/TAILINGS FROM GREGORY AND ARGO WERE TREATED
WITH EACH OF THE FOUR SELECTED FIXATION AGENTS. THE RESULTANT FIXED MATERIALS WERE THEN
SUBJECTED TO A SERIES OF LEACHING TESTS TO DOCUMENT THE EFFECTIVENESS OF THE TREATMENT. IN ALL
CASES, THE FIXATION AGENTS TESTED WERE EFFECTIVE IN REDUCING LEACHATE CONCENTRATIONS. IN SOME
CASES, LEACHATE CONCENTRATIONS WERE BELOW AWQC FOR ZINC. HOWEVER, IN ONE CASE, THE LEACHATE
CONTAINED EXTREMELY HIGH VALUES FOR ALUMINUM (27,700 UG/L). BECAUSE OF THIS RESULT, THIS
FIXATION AGENT WAS ELIMINATED FROM EVALUATION. KILN DUST AND TWO PROPRIETARY AGENTS WERE ALL
CONSIDERED FURTHER. BASED ON COST AND LEACHATE QUALITY, KILN DUST IS THE MOST COST-EFFECTIVE.
KILN DUST WOULD BE APPLIED AT AN APPLICATION RATE OF APPROXIMATELY 0.58 TONS PER CUBIC YARD OF
AVAILABLE TAILINGS AND WASTE ROCK MATERIAL. APPROXIMATELY 9 INCHES OF KILN DUST WOULD BE MIXED
0 WITH THE TOP 9 INCHES OF TAILINGS AND WASTE ROCK MATERIAL AND THEN COMPACTED.
FIXATION OF THE TAILINGS AND WASTE ROCK PILES IS A PERMANENT SOLUTION THAT REMOVES EXPOSURE TO
HUMAN HEALTH AND THE ENVIRONMENT.
REPROCESSING ALTERNATIVE: THE REPROCESSING ALTERNATIVE CONSIDERS THE TAILINGS AND WASTE ROCK
PILES AS AN ECONOMIC RESOURCE AND RECOVERS THE INHERENT MONETARY VALUE WHILE GENERATING A WASTE
WHICH MAY NOT BE DETRIMENTAL TO THE ENVIRONMENT. IN ORDER TO EVALUATE THIS OPTION, A
THREE-PHASE CHARACTERIZATION TASK WAS UNDERTAKEN:
- EVALUATING THE PARAMETERS NECESSARY TO PROCESS THE WASTE ROCK/TAILINGS;
- DETERMINING IF THE RESULTANT WASTE IS A HAZARDOUS WASTE; AND
- PERFORMING A COST ANALYSIS OF ALL OPTIONS.
THE REPROCESSING STUDIES WERE CONDUCTED ON A BENCH SCALE LEVEL BY INTERNATIONAL PROCESS RESEARCH
CORPORATION OF GOLDEN, COLORADO. TWO OPTIONS WERE EVALUATED, NAMELY:
- REPROCESSING OF ALL MATERIALS; AND
- REPROCESSING OF ALL MATERIALS LESS THAN TWO INCHES WITH DISPOSAL OF COARSE FRACTION AS
A WASTE ROCK.
THE RESULTS OF THESE TYPES OF TESTS WERE EVALUATED TO DETERMINE IF THE TAILINGS AND WASTE ROCK
COULD BE REPROCESSED. THESE TESTS INCLUDED:
- TESTS ON CHARACTERIZING THE WASTE ROCK WITH RESPECT TO PARTICLE SIZE DISTRIBUTION AND
SELECTED CONTAMINANT CONCENTRATIONS (COPPER, ZINC, LEAD, CHROMIUM, AND ARSENIC),
TOTAL SULFUR, AND PRECIOUS METALS (SILVER AND GOLD) IN DIFFERENT SIZE FRACTIONS;
- FROTH FLOTATION TESTS FOR RECOVERY OF AN ECONOMIC PRODUCT; AND