Draft Environmental Impact Statement for Roca Honda Mine

Contents
Glossary ...................................................................................................................................... 455
References Cited ........................................................................................................................ 457
Index ........................................................................................................................................... 491
List of Tables
Table S-1. Summary of potential environmental impacts associated with the project ............... viii
Table S-2. Potential permits and approvals ................................................................................... xi
Table 1. Summary of scoping comments received on the proposed Roca Honda Mine EIS .... 10
Table 2. Proposed reclamation seed mix for the Roca Honda Mine ......................................... 50
Table 3. Impact comparison matrix .......................................................................................... 63
Table 4. Range of constituents – San Mateo Creek and Marquez Canyon samples ............... 123
Table 5. Summary of hydrologic characteristics of hydrogeologic
units in the San Juan structural basin ........................................................................ 127
Table 6. Summary of aquifer characteristics in the vicinity of the Roca Honda permit area . 133
Table 7. Radionuclide data from permit area water monitoring wells .................................... 135
Table 8. Water chemistry of spring samples ........................................................................... 140
Table 9. Potential site storm water contaminants from equipment and nonequipment .......... 148
Table 10. Estimated types and quantities of excavated materials at the Roca Honda Mine ..... 150
Table 11. Estimated storm water runoff for developed and undeveloped conditions ............... 152
Table 12. Storm water controls for stockpiles .......................................................................... 153
Table 13. Potential sources of storm water contamination ....................................................... 153
Table 14. Temporary and permanent best management practices ............................................ 154
Table 15. Anticipated Roca Honda Mine influent water quality to treatment plant ................. 157
Table 16. Stratigraphic identification and calibrated hydraulic properties of each
hydrogeologic unit used in the RHR groundwater model of the San Juan Basin
and ratio between horizontal and vertical hydraulic conductivities for each unit ..... 163
Table 17. Predicted dewatering phases and rates at the Roca Honda Mine .............................. 165
Table 18. Groundwater modeling scenarios for Roca Honda Mine .......................................... 165
Table 19. San Juan Basin water balance: pre-development vs. current condition .................... 166
Table 20. Predicted change in San Juan Basin water balance from RHR Mine;
positive numbers are inputs and negative numbers are outputs, in total acre-feet .... 167
Table 21. Predicted drawdown caused by dewatering at the Roca Honda Mine ...................... 167
Table 22. NAAQS and monitored levels of criteria pollutants ................................................. 180
Table 23. Class I areas in New Mexico and their distance from the proposed site................... 184
Table 24. Levels of impact for air quality ................................................................................. 186
Table 25. RHR’s proposed project emissions compared to de minimus thresholds ................. 188
Table 26. Estimated net CO2 emissions for the proposed Roca Honda Mine .......................... 193
Table 27. Comparison of vegetation classifications in areas of potential impact ..................... 204
Table 28. USFWS-listed endangered, threatened, or candidate plants,
McKinley and Cibola Counties ................................................................................. 204
xiv DEIS for Roca Honda Mine, Cibola National Forest