Subsidence and its Hydrologic and Socioeconomic E ffects

1. Subsidence and its Hydrologic and Socioeconomic Effects Brigham Young University Department of Civil and Environmental Engineering

2. Acknowledgments • Bureau of Land Management • Jeff McKenzie • Skyline and Sufco Mines • Division of Oil, Gas, and Mining • Kevin Lundmark • U.S. Forest Service • Brigham Young University • Rollin Hotchkiss • Karsten Busby • Keelan Jensen • Trace Farmer

3. Purpose and Scope • Purpose • Conduct a socioeconomic analysis of the impacts of subsidence • Analyze hydrologic data available online and relate to impacts of subsidence • Scope • State of Utah • Restricted to two mines (Skyline and Sufco) • Use as example and pattern for future analyses

4. Road Map • Case Studies • Socioeconomics • Mitigation • Hydrology • Recommendations

5. Subsidence Video from www.minesub.nsw.gov.au

6. 2 Case Studies • Skyline Mine- Burnout Creek • Sufco Mine- North Water Spring

7. Skyline Mine- Burnout Creek

9. Burnout Creek • CloselyMonitored • Topography • Sediment • Flow • Biology • Some topographical changes • No impact on flow

10. Burnout Creek

11. Sufco Mine- North Water Spring Area

12. North Water Spring Area

13. North Water Spring Area • Undermined by 2 long wall panels (2005-2006) • Loss of surface flow in springs: • Pines 105 • Pines 310 • Pines 311 • Joes Mill Pond

14. North Water Spring Area

15. North Water Spring Area • Impacts • Loss of 7,200 gallons per day of stock watering • Reduction and loss of riparian area • Water is not lost to watershed

16. North Water Spring Area

17. North Water Spring Area

18. North Water Spring Area

19. Comparison

20. Socioeconomics

21. Socioeconomics • Includes: • Value of Coal Produced from impacted areas • Value of negative impacts

22. Socioeconomics- Burnout Creek • To avoid undermining the Burnout Creek area: • 6 long wall panels in the upper coal seam • 4 long wall panels in the lower coal seam • 2 million tons of recoverable coal would be lost* *Estimate from Skyline Mine Subsidence Study

23. Socioeconomics- Burnout Creek

24. Socioeconomics- Burnout Creek • No negative socioeconomic impacts were noted • No significant effects to biology or streamflow

25. Socioeconomics- North Water Spring • To avoid undermining the North Water Spring area: • long wall panels 5LPE and 6LPE would not be mined • about 8.6 million tons of recoverable coal would be lost

26. Socioeconomics- North Water Spring

27. Socioeconomics- North Water Spring • Negative Impacts • Allotment is grazed for 20 days each summer • 1400 head of cattle • If no water were provided, grazing would not be possible • Provide hay for cattle • Sell cattle

28. Socioeconomics- North Water Spring Negative impacts on grazing:

29. Socioeconomics- North Water Spring • Comparison- Coal and Cattle

30. Socioeconomics- North Water Spring • Other impacts include • Loss of riparian area • Loss of habitat for plant and animal species • Quantifiable losses if: • Endangered species are involved • Significant percentage of a population is lost • Significant recreational use is lost

31. Mitigation

32. Current Efforts • Attempts to seal tension cracks • Bentonite curtains installed • Water provided to cattle • Possible water collection system

33. Current Efforts

34. Off-Site Mitigation

35. Off-Site Mitigation • History of off-site mitigation • Jordanelle Reservoir • Land near Currant Creek and through Hobble Creek were purchased to replace deer habitat • I-15 Corridor • Wetland banking • Limited mitigation options in immediate North Water Spring area

36. Hydrology

37. Hydrology • Available data- DOGM Database • Not very user friendly • No spatial information • Interactive Map

38. Palmer Hydrological Drought Index

39. Palmer Hydrological Drought Index

40. Recommendations

41. Recommendations • Better water monitoring • Electronic monitoring • Better soil analysis previous to mining • Not an isolated incident • Betterdata presentation • More creativity when considering mitigation