Dames & Moore, 1999 - USDA Forest Service

6.4.3 Evidence of Oxidation of Chalcopyrite ............................................................... 6-20
6.4.4 Evidence of Acid-Buffering by Minerals ........................................................... 6-21
6.4.5 Evidence of Metal Attenuation ........................................................................... 6-22
6.4.6 Conclusions .................................................................... ................................... 6-23
6.5 GEOGRAPHICAL DESCRIPTION OF CHEMICAL PROCESSES ..... : ................... 6-24
6.5.1 Air and Water Movement Associated with the Honeymoon Heights and
Mine Support Areas ........................................................................................ 6-25
6.5.2 Tailings Piles ...................................................................................................... 6-35
6.6 RAILROAD CREEK ................................................................................................... 6-39
6.6.1 Surface Water Loading Analysis ........................................................................ 6-39
6.7 COMPARISON OF THE HOLDEN MINE WITH OTHER MINE SITES ................ 6-46
6.7.1 Baker Mine ......................................................................................................... 6-46
6.7.2 Sullivan Mine ..................................................................................................... 6-47
6.7.3 Conclusions ......................................................................................................... 6-48
6.8 FLOCCULENT AND FERRICRETE ......................................................................... 6-49
6.8.1 Flocculent ........................................................................................................... 6-49
6.8.2 Ferricrete Formation ........................................................................................... 6-49
6.9 SEDIMENT ..... ................................... ..................................................................... 6-50
6.10 CONCLUSIONS ........................................................................................................... 6-51
7.0 BASELlNE RISK ASSESSMENT ....................................... ...................................................... 7-1
7.1 HUMAN HEALTH RISK ASSESSMENT ................................................................... 7-1
7.1.1 Methodology ......................................................................................................... 7-1
7.1.2 Data Evaluation ..................................................................................................... 7-3
7.1.3 Screening Level Human Health Assessment ........................................................ 7-7
7.1.4 Site-specific Human Health Risk Assessment .................................................... 7-24
7.1.5 Conclusions of Baseline Human Health Risk Assessment .............................. 7-35
7.2 ECOLOGICAL RISK ASSESSMENT ..................... { ................................................. 7-38 '3
...................................................
7.2.1 Methodology .............................. ................... 7-38
I
7.2.2 Baseline Problem Formulation ........................................................................... 7-40
7.2.3 Analysis .............................................................................................................. 7-46
7.2.4 Risk Characterization ............................................. ............................................. 7-61
7.2.5 SOURCES OF UNCERTAINTY ....................................................................... 7-7 1
7.2.6 Conclusion 7-76 1
..........................................................................................................
8.0 DISCUSSION AND INTERPRETATION OF FINDINGS ....................................................... 8-1
8.1 ' INTRODUCTION .......................................................................................................... 8-1
.......................
8.2 INTERPRETATION OF THE SITE SETTING .................................... 8-1
8.2.1 Physiography ......................................................................................................... 8-1
8.2.2 Geology ............................................................. : .................................................. 8-3
8.2.3 Surface Water ......................................... : .............................................................. 8-8
8.2.4 Groundwate ....................................................................................................... 8-14
8.2.5 Other Physical Site Feature ............................................................................. 8-17
8.2.6 Ecological Conditions ......................................................................................... 8-18
8.3 SITE CONTAMINANT CHARACTERIZATION ...................................................... 8-26
8.3.1 Introduction ........................................................................................................ 8-26
8.3.2 Soil ............... : ...................................................................................................... 8-26
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17693-005-019UuIy 29 . 1999;12:54 PM;DRAFT FINAL RI REPORT
v DAMES & MOORE
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