Prepared in cooperation with the 

USDA Forest Service

U.S. Bureau of Land Management

U.S. Environmental Protection Agency

Integrated Investigations of Environmental Effects of 

Historical Mining in the Animas River Watershed, 

San Juan County, Colorado

Professional Paper 1651

U.S. Department of the Interior

U.S. Geological Survey
Cover. Red Mountains #1 through #3, viewed left to right looking east from the USDA Forest Service 

information stop near Red Mountain Pass, Colorado, September 2003. The colors of these red 

mountains illustrate the extent of alteration within the Silverton caldera that is responsible for the 

ore deposits and that also affects the water quality of streams. The panorama is digitally stitched 

(Briant A. Kimball).
Integrated Investigations of Environmental 

Effects of Historical Mining in the Animas 

River Watershed, San Juan County, 

Colorado

Edited by Stanley E. Church, Paul von Guerard, and Susan E. Finger

Prepared in cooperation with the

U.S. Department of Agriculture (USDA) Forest Service

U.S. Bureau of Land Management

U.S. Environmental Protection Agency

Professional Paper 1651

U.S. Department of the Interior

U.S. Geological Survey

The Animas River watershed study comprises two volumes.

Volume 1 contains Chapters A, B, C, D, and E1–E10.

Volume 2 contains Chapters E11–E25, F, and G,

and an accompanying CD-ROM

Volumes 1 and 2
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

First printing: 2007

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Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Church, S.E., von Guerard, Paul, and Finger, S.E., eds., 2007, Integrated investigations of environmental effects of 

historical mining in the Animas River watershed, San Juan County, Colorado: U.S. Geological Survey Professional 

Paper 1651, 1,096 p. plus CD-ROM. [In two volumes.]
iii

Contents

Volume 1

 A. Summary and conclusions from investigation of the effects of historical 

mining in the Animas River watershed, San Juan County, Colorado ...................................1

 By U.S. Geological Survey 

 B. The Animas River watershed, San Juan County, Colorado .................................................17

 By Paul von Guerard, Stanley E. Church, Douglas B. Yager, 

 and John M. Besser

 C. History of mining and milling practices and production in San Juan County, 

Colorado, 1871–1991 ...................................................................................................................39

 By William R. Jones 

 D. Impacts of historical mining on aquatic ecosystems—An ecological risk 

assessment ..................................................................................................................................87

 By John M. Besser, Susan E. Finger, and Stanley E. Church

 E. Watershed-Scale Characterization and Investigation of Processes 

Responsible for Environmental Effects of Historical Mining

 E1. Geologic framework .................................................................................................................107

 By Douglas B. Yager and Dana J. Bove

 E2. Imaging spectroscopy applied to the Animas River watershed and 

Silverton caldera .......................................................................................................................141

 By J. Bradley Dalton, Dana J. Bove, Carol S. Mladinich, 

 and Barnaby W. Rockwell 

 E3. Major styles of mineralization and hydrothermal alteration and related 

solid- and aqueous-phase geochemical signatures ..........................................................161

 By Dana J. Bove, M. Alisa Mast, J. Bradley Dalton, Winfield G. Wright, 

 and Douglas B. Yager

 E4. Helicopter electromagnetic and magnetic surveys ............................................................231

 By Bruce D. Smith, Robert R. McDougal, Maryla Deszcz-Pan, 

 and Douglas B. Yager 

 E5. Mine inventory and compilation of mine-adit chemistry data ..........................................255

 By Stanley E. Church, M. Alisa Mast, E. Paul Martin, and Carl L. Rich

 E6. Mine adits, mine-waste dumps, and mill tailings as sources of contamination ............311

 By J. Thomas Nash and David L. Fey

 E7. Characterization of background water quality ....................................................................347

 By M. Alisa Mast, Philip L. Verplanck, Winfield G. Wright, 

 and Dana J. Bove

 E8. Aqueous-sulfate stable isotopes—A study of mining-affected and undisturbed 

acidic drainage .........................................................................................................................387

 By D. Kirk Nordstrom, Winfield G. Wright, M. Alisa Mast, Dana J. Bove, 

 and Robert O. Rye

 E9. Quantification of metal loading by tracer injection and synoptic sampling, 

1996–2000 ...................................................................................................................................417

 By Briant A. Kimball, Katherine Walton-Day, and Robert L. Runkel

 E10. Distribution of pH values and dissolved trace-metal concentrations in streams ..........497

 By Winfield G. Wright, William Simon, Dana J. Bove, M. Alisa Mast, 

 and Kenneth J. Leib 
iv

Volume 2

 E11. Characterization of mainstem streams using water-quality profiles ...............................543

 By Kenneth J. Leib, M. Alisa Mast, and Winfield G. Wright

 E12. Trace elements and lead isotopes in modern streambed and terrace 

sediment—Determination of current and premining geochemical baselines ...............571

 By Stanley E. Church, David L. Fey, and Daniel M. Unruh

 E13. Topographic, geophysical, and mineralogical characterization of geologic 

structures using a statistical modeling approach ...............................................................643

 By Robert R. McDougal, Anne E. McCafferty, Bruce D. Smith, 

 and Douglas B. Yager

 E14. Formation and geochemical significance of iron bog deposits ........................................689

 By Mark R. Stanton, Douglas B. Yager, David L. Fey, 

 and Winfield G. Wright

 E15. Ferricrete classification, morphology, distribution, and carbon-14 age 

constraints .................................................................................................................................721

 By Philip L. Verplanck, Douglas B. Yager, Stanley E. Church, 

 and Mark R. Stanton

 E16. Geomorphology of Cement Creek and its relation to ferricrete deposits ........................745

 By Kirk R. Vincent, Stanley E. Church, and Laurie Wirt

 E17. Geochemical and hydrologic processes controlling formation of ferricrete .................775

 By Laurie Wirt, Kirk R. Vincent, Philip L. Verplanck, Douglas B. Yager, 

 Stanley E. Church, and David L. Fey

 E18. Status of stream biotic communities in relation to metal exposure .................................823

 By John M. Besser and William G. Brumbaugh

 E19. Toxicity of metals in water and sediment to aquatic biota ................................................837

 By John M. Besser and Kenneth J. Leib

 E20. Effects of mining on benthic macroinvertebrate communities and 

monitoring strategy ..................................................................................................................851

 By Chester R. Anderson

 E21. Application of physical habitat simulation in the evaluation of physical habitat 

suitability ....................................................................................................................................873

 By Robert T. Milhous

 E22. Response of the upper Animas River downstream from Eureka to discharge 

of mill tailings .............................................................................................................................889

 By Kirk R. Vincent and John G. Elliott

 E23. Effects of the May Day mine site on stream-water quality in the Cement Creek 

basin, August 2000 ....................................................................................................................943

 By Winfield G. Wright, Briant A. Kimball, and Robert L. Runkel

 E24. Using the OTIS solute-transport model to evaluate remediation scenarios 

in Cement Creek and the upper Animas River .....................................................................973

 By Katherine Walton-Day, Suzanne S. Paschke, Robert L. Runkel, 

 and Briant A. Kimball

 E25. Processes affecting the geochemical composition of wetland sediment ....................1029

 By Mark R. Stanton, David L. Fey, Stanley E. Church, and Charles W. Holmes

 F. Potential for successful ecological remediation, restoration, and monitoring ............1065

 By Susan E. Finger, Stanley E. Church, and Paul von Guerard

 G. Digital databases and CD-ROM for the Animas River watershed ..................................1079

 By Tracy C. Sole, Matthew Granitto, Carl L. Rich, David W. Litke, 

 and Richard T. Pelltier