United States Office of Research and EPA/600/R-99/007 Environmental Protection Development February 1999 Agency Washington, D.C. 20460 Characterization of Mine Leachates and the Development of a Ground-Water Monitoring Strategy for Mine Sites EPA/600/R-99/007 February 1999 Characterization of Mine Leachates and the Development of a Ground-Water Monitoring Strategy for Mine Sites by Russell H. Plumb, Jr. Lockheed Martin Services Group Las Vegas, Nevada Contract Number 68-C5-0091 Project Officer Larry A. Eccles National Environmental Research Laboratory U.S. Environmental Protection Agency Las Vegas, Nevada Notice Although the research described in this report was supported by the U.S. Environmental Protection Agency, through its Office of Research and Development, it has not been subjected to Agency policy review and therefore does not necessarily reflect the views of the Agency. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. ii Acknowledgment This work was conducted under Work Assignments 224-20320 and LV4-20320 of Contract No. 68-C5- 0091 between the U.S. Environmental Protection Agency National Environmental Research Laboratory and the Lockheed Martin Services Group, Las Vegas, Nevada. The EPA Work Assignment Manager on this task was Larry A. Eccles. The monitoring records for Nevada heap leaching facilities were obtained from the Bureau of Mining Regulation and Reclamation, Nevada Department of Environmental Protection. The assistance and cooperation of Douglas Zimmerman and Matt McAuliffe in obtaining this information is acknowledged and appreciated. The monitoring records for Arizona copper mining facilities were obtained from the Arizona Department of Environmental Quality. The assistance and cooperation of Charles Graf, Michael Wood, and Gregory Olsen is acknowledged and appreciated. The assistance of Gregory Raab in compiling and reviewing some of the Arizona copper mine data is also acknowledged. iii Table of Contents Page Notice ......................................................................... ii Acknowledgment ................................................................iii Table of Contents ................................................................iv List of Figures ................................................................. vii List of Tables .................................................................. xv 1.0 Introduction ...............................................................1-1 2.0 Data Collection ............................................................2-1 2.1 Data Sources ..........................................................2-1 2.2 Data Compilation .......................................................2-3 2.3 Quality Assurance Considerations .........................................2-4 2.3.1 Accuracy Data Quality Objective ....................................2-4 2.3.2 Precision Data Quality Objectives ....................................2-5 2.3.3 Completeness Data Quality Objective .................................2-7 2.3.4 Comparability Data Quality Objective .................................2-7 3.0 Chemical Composition of Mine Waste Leachates ..................................3-1 3.1 Heap Leaching Process Solution ...........................................3-1 3.2 Meteoric Water Mobility Test Leachates ....................................3-6 3.3 Tailings Ponds at Copper Mines ...........................................3-9 3.4 Summary .............................................................3-9 4.0 Characterizing Solution Compositions Using Multiple-ion Fingerprint Patterns ..........4-1 4.1 Stiff Diagrams as a Multivariate Characterization Technique ....................4-2 4.2 Characterization of Incinerated Municipal Waste Ash Leachates .................4-2 4.3 Application to Mine Waste Leachate Characterization .........................4-10 4.4 Stiff Diagram Modifications .............................................4-10 4.5 Summary ............................................................4-11 5.0 Assessment of Monitoring Results From Gold Heap Leaching Facilities in Nevada .......5-1 5.1 Description of Heap Leaching Process ......................................5-1 5.2 Fingerprinting Heap Leaching Process Solutions ..............................5-3 5.2.1 Lone Tree Gold Mine ..............................................5-4 iv 5.2.2 Green Springs Gold Mine ......................................... 5-14 5.2.3 Alligator Ridge Mine ............................................. 5-20 5.2.4 Oliver Hills Mine ................................................ 5-25 5.2.5 Barrick Goldstrike Mine .......................................... 5-30 5.2.6 Rabbit Creek Mine ............................................... 5-41 5.2.7 Aurora Partnership Mine .......................................... 5-48 5.2.8 Cortez Gold Mine ............................................... 5-54 5.2.9 Florida Canyon Mine ............................................. 5-70 5.2.10 Alta Gold Mine ................................................. 5-77 5.2.11 Hycroft Gold Mine .............................................. 5-84 5.2.12 Paradise Peaks Mine ............................................. 5-90 5.2.13 First Miss Getchell Gold Mine ..................................... 5-95 5.2.14 Arimetco Gold Mine ............................................ 5-101 5.2.15 Nevada Goldfield Sleeper Mine ................................... 5-108 5.2.16 Corona Gold Mine .............................................. 5-116 5.2.17 Bullfrog Gold Mine ............................................. 5-118 5.2.18 Marigold Gold Mine ............................................ 5-124 5.2.19 Chimney Creek Gold Mine ....................................... 5-127 5.2.20 Bald Mountain Gold Mine ........................................ 5-136 5.2.21 American Eagle Flowery Mine .................................... 5-142 5.2.22 Other Heap Leaching Sites ....................................... 5-146 5.3 Discussion of Heap Leaching Case Studies ................................ 5-147 5.4 Heap Leaching Summary .............................................. 5-153 6.0 Assessment of Monitoring Results From Tailings Basins at Arizona Copper Mines ...... 6-1 6.1 Twin Butte Copper Mine ................................................ 6-1 6.1.1 Tailings Leachate Characterization ................................... 6-2 6.1.2 Laboratory Column Studies ......................................... 6-7 6.1.3 Field Monitoring Results ........................................... 6-8 6.1.4 Twin Butte Summary ............................................. 6-26 6.2 Phelps-Dodge Tailings Disposal Area ..................................... 6-27 6.2.1 Characterization of Phelps-Dodge Tailings Leachate .................... 6-28 6.2.2 Assessment of Ground-Water Conditions ............................. 6-37 6.2.3 Assessment of Surface Water Conditions ............................. 6-44 6.2.4 Phelps-Dodge Tailings Disposal Area Summary ....................... 6-49 6.3 Cyprus Sierrita Copper Mine ............................................ 6-49 6.3.1 Tailings Leachate Characterization .................................. 6-51 6.3.2 Ground-Water Monitoring Results .................................. 6-51 6.3.3 Cyprus Sierrita Summary .......................................... 6-52 6.4 Zonia Copper Mine .................................................... 6-57 6.4.1 Background Ground-Water Conditions ............................... 6-57 6.4.2 Downgradient Ground-Water Conditions ............................. 6-57 6.4.3 Zonia Summary ................................................. 6-58 6.5 Discussion of Copper Mine Case Studies ................................... 6-59 6.6 Arizona Copper Mines Summary ......................................... 6-67 v 7.0 Development of a Ground-Water Monitoring Strategy for Mining Facilities .............7-1 7.1 Background ...........................................................7-1 7.2 Need for Monitoring ....................................................7-1 7.3 Monitoring Parameter Criteria ............................................7-3 7.4 Proposed Monitoring Strategy .............................................7-9 7.5 Implementation of Proposed Monitoring Strategy ............................7-11 7.5.1 Phase I. Source Characterization ....................................7-12 7.5.2 Detection Monitoring .............................................7-14 7.5.3 Assessment Monitoring ...........................................7-15 7.5.4 Corrective Action ................................................7-16 7.6 Discussion ...........................................................7-16 7.7 Summary ............................................................7-22 8.0 Summary ...............................................................8-1 9.0 References ...............................................................9-1 vi List of Figures Figure Number/Description Page 3-1 Composite process solution monitoring results ................................... 3-3 3-2 Composite Meteoric Water Mobility Test leaching results ......................... 3-8 3-3 Composite monitoring results from copper mine tailings basins .................... 3-11 4-1 Example of Stiff Diagram used to characterize the composition of mine waste leachates .. 4-2 4-2 Examples of characteristic nonpoint source fingerprints identified by Rahn et al. (1995) .. 4-3 4-3 Characteristic multivariant fingerprint