Final Site Information Package for National Remedy Review Board ...

More documents

Recommendations

Info

TABLE B9-1a Comparative Analysis of the No Action Alternative and Alternatives 3+(a) through 3+(e) Site Information Package for National Remedy Review Board Criteria No Action Overall Protection of Human Health and the Environment Controls used to reduce risks No actions to reduce risks. Existing unacceptable risks to ecological receptors would remain unabated. Potential human health risks would remain unchanged. Effectiveness summary Contaminants would limit recovery of habitat structure and ecosystem function. ARARs summary No actions would be conducted to reduce AWQC ratios, which are estimated to be 5.5 at Elizabeth Park and 4.3 at Pinehurst. OU 2 Alternative (a) Minimal Stream Lining OU 2 Alternative (b) Extensive Stream Lining OU 3 Component Alternative 3+: More Extensive Removal, Disposal, and Treatment OU 2 Component OU 2 Alternative (c) French Drains OU 2 Alternative (d) Stream Lining/French Drain Combination OU 2 Alternative (e) Extensive Stream Lining/French Drain Combination Combined Upper Basin Alternative Alternative 3+(a) Alternative 3+(b) Alternative 3+(c) Alternative 3+(d) Alternative 3+(e) Under Alternative 3+(a), environmental risks would be reduced by removing tailings-impacted alluvium and waste rock from the 100-year floodplain, containing/stabilizing other high-level wastes in-place, treatment of most adit drainage, and hydraulic isolation and groundwater treatment at tailings impoundments and river reaches. Intensive stream and riparian improvements and creation of off-channel hydrologic units would improve stream stability. Dredging of sediment traps would reduce bedload transport. Potential human health risks would be addressed by the above actions and additional access restrictions. Decontamination of structures would further address potential human health risks. The OU 2 stream liners would reduce the infiltration of relatively clean surface water into contaminated subsurface materials beneath OU 2, and thereby reduce metals loading from groundwater to surface water in the downstream gaining reaches. Would effectively contain media with high to intermediate loading potential, and improve recovery of ecosystem function. Overall moderate load reduction (42 percent at Pinehurst). Natural source depletion processes would further reduce residual risk. Overall moderate AWQC-ratio reduction (2.8 compared to 4.3) for Pinehurst. Attainment of ARARs for surface water would require a period of natural source depletion See Alternative 3+(a). In addition, this alternative would provide more extensive stream lining throughout the Bunker Hill "Box". Extraction wells and slurry walls would also be included in some Box tributaries to collect clean groundwater for discharge to the lined stream. Would effectively contain media with high to intermediate loading potential, and improve recovery of ecosystem function. Overall moderate load reduction (41 percent at Pinehurst). Natural source depletion processes would further reduce residual risk. See Alternative 3+(a). Alternative differences include no stream lining and the addition of French drains in the Box. Direct piping of the CTP effluent to the SFCDR is also included. Would effectively contain media with high to intermediate loading potential, and improve recovery of ecosystem function. Overall large load reduction (60 percent at Pinehurst). Natural source depletion processes would further reduce residual risk. Overall moderate AWQC-ratio Overall large AWQC-ratio reduction (1.5 reduction (2.8 compared to 4.3) for compared to 4.3) for Pinehurst. Pinehurst. Attainment of ARARs for Attainment of ARARs for surface water surface water would require a period of would require a period of natural source natural source depletion depletion Page 1 of 6 See Alternative 3+(c). The only See Alternative 3+(a). In addition, this difference between this alternative and alternative includes extensive stream Alternative 3+(c) is that this alternative lining with slurry walls and extraction also has a stream liner in Government wells for groundwater collection, as well Gulch, with a slurry wall and extraction as French drains along the SFCDR. wells at the upstream end for discharge The extensive actions included in this of clean groundwater to the lined stream alternative would effectively decouple channel. Direct piping of the CTP the groundwater and surface water effluent to the SFCDR is also included. systems through the Box. Would effectively contain media with high to intermediate loading potential, and improve recovery of ecosystem function. Would provide slightly higher effectiveness than Alternative 3+(c ) by providing additional benefits to the water quality in Government Creek. Overall large load reduction (62 percent at Pinehurst). Natural source depletion processes would further reduce residual risk. Overall large AWQC-ratio reduction (1.5 compared to 4.3) for Pinehurst. Attainment of ARARs for surface water would require a period of natural source depletion Would effectively contain media with high to intermediate loading potential, and improve recovery of ecosystem function. In addition, significantly more aggressive actions would be implemented in the Box. Overall large load reduction (66 percent at Pinehurst). Natural source depletion processes would further reduce residual risk. Overall large AWQC-ratio reduction (1.3 compared to 4.3) for Pinehurst. Attainment of ARARs for surface water would require a period of natural source depletion
TABLE B9-1a Comparative Analysis of the No Action Alternative and Alternatives 3+(a) through 3+(e) Site Information Package for National Remedy Review Board Criteria No Action Compliance with ARARs Chemical-specific ARARs Would not comply with chemicalspecific ARARs (AWQC) for surface water until natural decay processes reduced loading to below AWQC levels (see ARARs summary above). Location- and action-specific ARARs Long-Term Effectiveness and Permanence Magnitude of residual risk Magnitude of existing ecological risk may decrease slightly or remain essentially unchanged for several decades or centuries. Adequacy and reliability of controls OU 2 Alternative (a) Minimal Stream Lining OU 3 Component Alternative 3+: More Extensive Removal, Disposal, and Treatment OU 2 Component OU 2 Alternative (b) OU 2 Alternative (c) OU 2 Alternative (d) Stream Lining/French Drain Extensive Stream Lining French Drains Combination OU 2 Alternative (e) Extensive Stream Lining/French Drain Combination Combined Upper Basin Alternative Alternative 3+(a) Alternative 3+(b) Alternative 3+(c) Alternative 3+(d) Alternative 3+(e) Would significantly reduce metals concentrations in surface water, but would not meet surface water ARARs following remediation (see ARARs summary above). Not applicable Would comply with all action-specific and location-specific ARARs, including substantive requirements of CWA Section 404, Rivers and Harbors Act Section 10, and Endangered Species Act. Potential for ecosystem recovery is limited by contaminants. Potentially significant residual risks to humans. No controls would be implemented to control residual risks. Moderate reduction in expected postremediation mass loadings (estimated 42% reduction). Some smaller loading sources would receive no action or limited containment. Low potential for mobilization (through erosion) of contaminated alluvium left in place. Natural source depletion processes would further reduce residual risks. Low residual risk to humans. Decontamination of structures and access restrictions would be effective. Remedy could effectively be maintained through monitoring, maintenance, and institutional controls. Moderate maintenance requirements for caps, stream and riparian improvements, sediment traps, French drains, and stream liners. High maintenance requirements for passive and active treatment. Would significantly reduce metals concentrations in surface water, but would not meet surface water ARARs following remediation (see ARARs summary above). Would significantly reduce metals concentrations in surface water, but would not meet surface water ARARs following remediation (see ARARs summary above). Would significantly reduce metals concentrations in surface water, but would not meet surface water ARARs following remediation (see ARARs summary above). Would significantly reduce metals concentrations in surface water, but would not meet surface water ARARs following remediation (see ARARs summary above). See Alternative 3+(a). See Alternative 3+(a). See Alternative 3+(a). See Alternative 3+(a). See Alternative 3+(a). Additional Large reduction in expected post- benefits would be achieved through remediation mass loadings (estimated this alternative by significantly 60% reduction). Some smaller loading improving water quality in several OU 2 sources would receive no action or tributaries (Government, Magnet, and limited containment. Low potential for Deadwood Creeks). mobilization (through erosion) of contaminated alluvium left in place. Natural source depletion processes would further reduce residual risks. Low residual risk to humans. Decontamination of structures and access restrictions would be effective. Low residual risk to humans. Decontamination of structures and access restrictions would be effective. See Alternative 3+(a). See Alternative 3+(a). More linear feet of French drain are included in this alternative, although less stream lining. Page 2 of 6 Large reduction in expected postremediation mass loadings (estimated 62% reduction). Load reduction estimates provided are for the SFCDR. Additional benefits would be achieved through this alternative by significantly improving water quality in Government Creek. Some smaller loading sources would receive no action or limited containment. Low potential for mobilization (through erosion) of contaminated alluvium left in place. Natural source depletion processes would further reduce residual risks. Low residual risk to humans. Decontamination of structures and access restrictions would be effective. See Alternative 3+(a). More linear feet of French drain and slightly less stream lining would be included in this alternative. Large reduction in expected postremediation mass loadings (estimated 66% reduction). Additional benefits would be achieved through this alternative by significantly improving water quality in many OU 2 tributaries. Some smaller loading sources would receive no action or limited containment. Low potential for mobilization (through erosion) of contaminated alluvium left in place. Natural source depletion processes would further reduce residual risks. Low residual risk to humans. Decontamination of structures and access restrictions would be effective. See Alternative 3+(a). Significantly more stream lining and French drains would be included in the alternative, as well as slurry walls and groundwater extraction wells.
Page 1 and 2:
United States Environmental Protect
Page 3 and 4:
Contents Acronyms and Abbreviations
Page 5 and 6:
SITE INFORMATION PACKAGE FOR NATION
Page 7 and 8:
Page 9 and 10:
Acronyms and Abbreviations µg/dL m
Page 11 and 12:
RAO remedial action objective RI/FS
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
1. Site Name, Location, and Brief H
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
5. Current and Potential Future Sit
Page 49 and 50:
6. Summary of Risks The Bunker Hill
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
8. Description of Alternatives The
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Remedial Alternative Description SI
Page 67 and 68:
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
12. Potential Applicable or Relevan
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
COMMISSIONERS: PFfifiY WHITF CLERK
Page 95 and 96:
Dan Opalski, U.S. EPA March 10,2010
Page 97 and 98:
Dan Opalski, U.S. EPA March 10, 201
Page 99:
Dan Opalski, U.S. EPA March 10,2010
Page 112 and 113: SITE INFORMATION PACKAGE FOR NATION
Page 118 and 119: Rose Lake ll n e §¨¦ 90 DUDLEY "
Page 120 and 121: 1992-1994 Removal of tailings and c
Page 122 and 123: The box plot shows the median or 50
Page 124 and 125: ! ( ! ! ( ! ! ! Upper Basin Coeur d
Page 126 and 127: DUDLEY ") §¨¦ 90 ") St Joe River
Page 128 and 129: Base Map Data: NHDPlus (Rivers, Wat
Page 130 and 131: [Two Updated Updated Woodland Ecolo
Page 132 and 133: Ninemile Creek WALLACE BUNN Upper B
Page 134 and 135: OSBURN §¨¦ 90 Upper Basin Coeur
Page 136 and 137: 176 E Upper Basin Coeur d'Alene Riv
Page 138 and 139: §¨¦ 90 ENAVILLE The Bunker Hill
Page 140 and 141: E 169 §¨¦ 90 Upper Basin Coeur d
Page 142 and 143: TABLE B2-1 Summary of Ongoing Data
Page 144 and 145: TABLE B4-2 Screening Level Exceedan
Page 146 and 147: TABLE B7-1 Preliminary Remediation
Page 148 and 149: TABLE B8-1 Descriptions of Typical
Page 150 and 151: TABLE B8-2 Summary of Alternatives
Page 154 and 155: TABLE B9-1a Comparative Analysis of
Page 156 and 157: TABLE B9-1a Comparative Analysis of
Page 158 and 159: TABLE B9-1b Comparative Analysis of
Page 164 and 165: TABLE B11-1 Legend of Bureau of Lan
Page 166 and 167: TABLE B11-1 Legend of Bureau of Lan
Page 168 and 169: TABLE B11-2 Summary of Estimated Po
Page 170 and 171: TABLE B11-4 Summary of Remedy Prote
Page 172 and 173: TABLE B14-1 Estimated Costs Summari
Page 174 and 175: TABLE B14-2 Summary of Estimated Co
Page 176: TABLE B14-2 Summary of Estimated Co
show all

Final Site Information Package for National Remedy Review Board ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?