2009-09-25_PERMIT FILE - M2009076 ‎(22)‎

• Permit No: M2009076
• IBM Index Class Name: PERMIT FILE
• Doc Date: 9/25/2009
• Doc Name: New 110d DMO Appl- Part I
• From: Venture Resources, Inc.
• To: DRMS
• Media Type: D
• Archive: No

ROCK PILE. THIS UNDERCUTTING HAS RESULTED IN SOME FAILURE OF THE BIG FIVE PILE AND HAS CAUSED
THE CURRENT UNSTABLE CONDITIONS.
COMMENT: REGARDING THE CONCLUSION IN THE FS REPORT THAT THE MINE TAILINGS MUST BE CLEANED UP TO
VENT THEM FROM WASHING DOWNSTREAM AND CONTAMINATING THE GOLDEN WATER SUPPLY DURING A FLOOD, A
iQING ENGINEER SAID THAT UNDER FLOOD CONDITIONS, THE CREEKS WOULD BE CONTAMINATED WITH OR
WITHOUT MINE TAILINGS. THE GOLDEN WATER SUPPLY WOULD BE CONTAMINATED FROM MANY SOURCES IN
ADDITION TO MINE TAILINGS, SO THE CONCLUSION THAT POTENTIAL FLOOD CONDITIONS JUSTIFY SLOPE
STABILIZATION IS NOT SUPPORTABLE. HE COMMENTED THAT EPA SHOULD FOCUS ITS ATTENTION ON PREPARING
THE GOLDEN WATER TREATMENT PLANT FOR FLOOD CONDITIONS RATHER THAN ATTEMPTING TO STABILIZE THE
TAILINGS AND WASTE ROCK PILES IN THE AREA. THE MAYOR OF IDAHO SPRINGS ALSO COMMENTED THAT THE
RI REPORT "... ASSUMES A WORST CASE SCENARIO, THE COLLAPSE OF TAILINGS FROM A 500-YEAR FLOOD
COLLAPSING INTO LOW STREAM FLOW CONDITIONS. IT WOULD TAKE FLOOD CONDITIONS TO CAUSE COLLAPSE.
FLOOD CONDITIONS ARE NOT LOW STREAM FLOW CONDITIONS. I BELIEVE THESE CONDITIONS ARE MUTUALLY
EXCLUSIVE, AND THAT 'WORST CASE CONDITION' IS NOT POSSIBLE.".
SPA'S RESPONSE: THE RI REPORT CONSIDERED A REALISTIC SCENARIO. SIMPLY, THE VOLUME OF WASTE ROCK
CURRENTLY EVALUATED TO BE UNSTABLE WAS PLACED IN THE RIVER UNDER LOW FLOW CONDITIONS. UNDER
FLOOD CONDITIONS, THE VOLUME OF UNSTABLE WASTE ROCK WOULD HAVE BEEN MUCH GREATER THAN THAT USED
IN THE EVALUATION.
CURRENTLY, GOLDEN CAN TREAT CONTAMINATED WATER. IT CANNOT TREAT LARGE VOLUMES FOR LONG PERIODS
OF TIME, HOWEVER. IT IS EPA'S POSITION TO PREVENT CONTAMINATION RATHER THAN TREAT IT AFTER THE
FACT.
COMMENT: SEVERAL RESIDENTS COMMENTED THAT THEY AND OTHERS HAD GROWN UP IN THE AREA AND HAVE
NEVER EXPERIENCED ADVERSE HEALTH EFFECTS FROM THE TAILINGS. MANY RESIDENTS EXPRESSED SKEPTICISM
THAT HEALTH RISKS WERE OF ANY SIGNIFICANCE. ONE COMMENTER SAID THAT THE FS REPORT AND PROPOSED
PLAN PRESENTED DATA THAT DID NOT SHOW OR EXPLAIN RISKS OR REACH ANY CONCLUSIONS OR
RECOMMENDATIONS ABOUT RISKS. HE SAID THAT STATISTICAL ESTIMATES OF RISK ALONE DID NOT HELP HIM
4v ERSTAND WHETHER SITE CONTAMINATION POSES A GENUINE THREAT TO HUMAN HEALTH.
EPA'S RESPONSE: RISK CALCULATIONS, SUCH AS THOSE PRESENTED IN THE PROPOSED PLAN AND IN THE FS
REPORT, PROVIDE ESTIMATES OF RISK. THESE ESTIMATES ARE BASED ON A CONSISTENT SET OF
ASSUMPTIONS, SO THAT THESE STANDARDS CAN BE APPLIED TO ALL TYPES OF CONDITIONS AND LOCATIONS AT
A VARIETY OF SUPERFUND SITES ACROSS THE COUNTRY. CURRENT EPA GUIDANCE STATES THAT THE RISK FOR
CARCINOGENIC MATERIALS AT A SITE SHOULD NOT EXCEED 10-4, AND PREFERABLY SHOULD BE LESS (E.G.,
10-7). THESE FIGURES REFER TO A RANGE OF RISKS THAT A POPULATION MAY FACE WHEN EXPOSED TO A
SPECIFIC HAZARD. FOR EXAMPLE, A 10-4 RISK IS THE RISK ASSESSORS' PROJECTION THAT A POPULATION
EXPOSED TO A PARTICULAR HAZARD MAY SUFFER ONE EXTRA CANCER DEATH PER 10,000 PERSONS; A RISK OF
10-7 MEANS THERE MIGHT BE ONE EXCESS CANCER DEATH PER 10,000,000 AMONG A POPULATION EXPOSED TO
THE HAZARD. THE RISKS AT THE CLEAR CREEK/CENTRAL CITY SITE ARE PRESENTED IN TABLE 1 OF THE ROD
AND IN CHAPTER 10 OF THE RI REPORT ISSUED JUNE 8, 1987. AS CAN BE SEEN IN TABLE 1, CURRENT
HUMAN HEALTH RISKS RESULTING FROM THE INHALATION AND INGESTION EXPOSURE PATHWAYS ARE MINOR.
HOWEVER, UNDER AN ASSUMED FUTURE RESIDENTIAL EXPOSURE SCENARIO, RISKS ARE PRESENT FOR PEOPLE WHO
MIGHT LIVE ON THE WASTE ROCK/TAILINGS PILES. THEREFORE, EPA HAS SELECTED THE NO ACTION
ALTERNATIVE FOR CURRENT EPISODIC USE OF THE PILES. FOR FUTURE RESIDENTIAL USE, EPA WILL WORK
WITH STATE AND LOCAL OFFICIALS TO PURSUE CONTROLS TO LIMIT FUTURE RESIDENTIAL DEVELOPMENT.
FOR NONCARCINOGENIC MATERIALS, EPA HAS ESTABLISHED MAXIMUM ACCEPTABLE EXPOSURES ("REFERENCE
DOSES") THAT SHOULD NOT BE EXCEEDED TO PROTECT HUMAN HEALTH.
COMMENT: A NEWSPAPER REPORTER COMMENTED THAT SOME OF THE WORDING IN THE FS REPORT AND OTHER
DOCUMENTS WAS TENTATIVE OR INEXACT. THE COMMENTER NOTED THAT AS A RESULT, EPA'S REMEDIAL ACTIONS
MAY NOT ACTUALLY OCCUR AS STATED OR MAY BE ONLY HYPOTHETICAL. SHE ALSO QUESTIONED SELECTION OF
PASSIVE TREATMENT AS A FINAL ALTERNATIVE WHEN IT IS STILL CONSIDERED EXPERIMENTAL. AN OWNER
OF ONE OF THE MINING PROPERTIES AT THE SITE COMMENTED ALSO THAT THE USE OF THE NO ACTION
TERNATIVE IN THE STUDY MADE NO SENSE AND WAS USED ONLY AS A "SCARE TACTIC" TO CONVINCE PEOPLE
THE NECESSITY OF EPA'S ACTIONS.
EPA'S RESPONSE: WHEN POSSIBLE, EPA WILL CHANGE THE WORDS TO BE MORE SPECIFIC. SELECTION OF THE
PASSIVE TREATMENT SYSTEM WAS PART OF THE REMEDY FOR OPERABLE UNIT ONE. PASSIVE TREATMENT
EFFECTIVENESS IS CURRENTLY BEING STUDIED AT A PILOT PLANT AT THE BIG FIVE. THESE DATA WILL BE