Analysis of Dredge Tailings Pile Patterns: Applications for Historical Archaeological Research AN ABSTRACT OF THE THESIS OF Sarah Elizabeth Purdy for the degree of Master of Arts in Applied Anthropology presented on June 7, 2007. Title: Analysis of Dredge Tailings Pile Patterns: Applications for Historical Archaeological Research. Abstract approved: ________________________________________________________________________________ Dr. David R. Brauner For centuries humans have been searching for precious metals. The search for gold has greatly changed the landscape of the American West, beginning in the 1850s and continuing today. Various gold rushes around the country created mining colonies in remote areas, thereby connecting the frontier with the rest of America and Europe. This research attempts to expand on the previous industrial archaeology literature, which focuses on historic mining sites and landscape patterns, by concentrating solely on dredge mining. This study analyzes dredge mining activity in the Elk City Township (T. 29 N., R. 8 E.) of North Central Idaho. Dredge mining leaves behind a mark on the landscape in the form of tailings piles, which are uniquely patterned due to different technologies. Through a detailed analysis of the tailings pile patterns, an archaeologist can determine what dredging technology was used, the time period of the operation, and the number of workers employed. In order to understand the technology used, part of this work is dedicated to the various forms of dredges that were used, along with the various dredge mining methods. This research provides a set of guidelines for archaeologists to properly document dredge tailings piles and determine their significance. The major contributions of this thesis are to clarify the historical context for dredge mining in North Central Idaho, to identify visible footprints left by this industrial activity, and to identify both pedestrian survey and remote sensing techniques to locate and differentiate between the various dredging technologies. The remote sensing techniques used include classifying Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) imagery and comparing it with digitally orthorectified photos (DOQ), to determine which imagery is more adept at detecting dredge tailings patterns. For better or worse, dredge mining has reshaped many areas in the American West. Currently, riverine and riparian restoration projects are destroying dredge tailings piles and attempting to return the river to its ‘original’ condition. However, these projects are destroying a piece of history that is not well understood and holds important information for archaeologists studying historic mining sites. This research will benefit not only archaeologists, but land managers as well, by explaining the significance of dredge tailings and providing them with a greater ability to protect and manage these irreplaceable resources. ©Copyright by Sarah Elizabeth Purdy June 7, 2007 All Rights Reserved Analysis of Dredge Tailings Pile Patterns: Applications for Historical Archaeological Research by Sarah Elizabeth Purdy A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Arts Presented June 7, 2007 Commencement June 2008 Master of Arts thesis of Sarah Elizabeth Purdy presented on June 7, 2007. APPROVED: Major Professor, representing Applied Anthropology Head of the Department of Anthropology Dean of the Graduate School I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request. Sarah Elizabeth Purdy, Author ACKNOWLEDGEMENTS I would like to thank all the individuals who have helped me through this process. My family has been there for me through everything; therefore, I would like to thank Mom, Dad, Stephen, Laura, and all my extended family for believing in me and supporting me. I have to especially thank my great grandma Thelma for inspiring me to follow my dreams, my grandma Judy for always being there for me, my grandma Helen for her support, and my grandpa Bill for instilling a love of the outdoors in me. I would also like to thank the BLM Cottonwood Field Office staff, especially David Sisson and Bob Lewis. Without David’s help and support I would not have had the opportunity to work in the Elk City area. He also helped me develop the idea for my thesis. Bob has been influential in teaching me more about mining; I only wish I could understand half of what Bob knows on this subject. I would like to thank the staff at Idaho Geologic Survey, especially Sherry Pixley, for providing me with all the historic mine information they have for the Elk City area. My summers of fieldwork were spent with archaeological crews and I would like to thank Cyrena Undem, Karen Belvin, Noelle Glines, and Tiffany Brunson, for the knowledge and insight about archaeology they shared with me, and for their patience with my obsession with historic mining sites. I would also like to thank Brooke Boulware for helping me with some fieldwork and always encouraging me along the way. I would especially like to thank my committee for their participation. I would like to thank Dr. David Brauner for serving as my major professor, reviewing my thesis multiple times, and encouraging me that dredge mining is an applicable thesis topic. I would like to thank Dr. Anne Nolin for serving as my minor advisor and for inspiring me to use remote sensing applications in archaeology. I would like to thank Dr. Loren Davis for all the hard work he spent revising and commenting on my work, and his help with the formulation of many ideas, charts, and maps. I would like to thank Dr. Tina Bull for serving as my graduate council representative and for being a mentor and inspiration in music to me for my entire college career. Lastly, I would like to thank Roxi Wolfe for her help in formatting this thesis. TABLE OF CONTENTS Page Chapter 1: Introduction ...................................................................................................... 1 1.1 Research Questions and Motivations ........................................................................ 4 1.2 Study Area ................................................................................................................. 7 Chapter 2: Literature Review ........................................................................................... 12 2.1 Industrial Landscape Archaeology .......................................................................... 12 2.2 Remote Sensing Applications for Dredge Mining .................................................. 20 Chapter 3: Dredge Mining and Methods .......................................................................... 24 3.1 Mechanical Dredge Mining .................................................................................... 24 3.1.1 Floating Dredges / Mechanical Continuous Systems ....................................... 27 3.1.2 Dryland Dredging / Mechanical Repetitive Systems ....................................... 32 3.2 Sediment Processing and Disposal ......................................................................... 34 3.3 Comparison of Dredge Mining Systems ................................................................. 40 3.4 Dredge Miners......................................................................................................... 42 Chapter 4: Dredge Mining in the Elk City Township ...................................................... 47 4.1 Historic Context of the Elk City Township ............................................................ 47 4.2 American River ....................................................................................................... 53 4.3 East Fork of the American River ............................................................................ 58 4.4 Buffalo Gulch .......................................................................................................... 58 4.5 Elk Creek ................................................................................................................. 60 4.6 Little Elk Creek ....................................................................................................... 61 4.7 South Fork Clearwater River .................................................................................. 62 4.8 Crooked River ......................................................................................................... 62 Chapter 5: Data Sets and Methods ................................................................................... 65 5.1 Data Sets and Software ........................................................................................... 65 5.1.2 Historical Information ...................................................................................... 65 5.1.3 Archaeological Surveys ................................................................................... 65 5.1.4 Satellite Imagery .............................................................................................. 66 5.1.5 Aerial Photography .......................................................................................... 67 5.2 METHODS ............................................................................................................. 68 5.2.1 Historical Information ...................................................................................... 68