William C. Ehler, P.G., Project Manager Office of Surface Mining

1. Has That New Home Taken Your Breath Away? Problems with Carbon Dioxide Infiltration into Residences Constructed Upon Reclaimed Surface Mines William C. Ehler, P.G., Project Manager Office of Surface Mining Appalachian Region, Federal Reclamation Program Pittsburgh, Pennsylvania 15220

2. CO2 Contamination Problems in Homes • “Blackdamp” • Usually associated with communication of shallow abandoned mine atmosphere with surface structures via old shafts & entries • 12 – 15 % CO2 in abandoned mine atmosphere • CO2 & Methane are natural products of coal

3. CO2 Replaces O2 and N2

4. Physiological Effects of Carbon Dioxide % CO2 in Air Increase in Respiration 0.03 ....................................... Normal Air & Respiration 0.05 ....................................... Slight Increase 0.5 ....................................... TLV-TWA (8-hr max by law) 2.0 ....................................... 50% more Respiration 3.0 ....................................... 100% more Respiration TLV-STEL (max by law) 5.0 ....................................... 300%, Laborious Breathing 10.0 ....................................... Cannot be endured, unconsciousness Concentrations over 0.5% CO2 produce relative decrease in O2.

5. Physiological Effects of Oxygen O2 - Percent Effect 21% ..........................Normal Breathing 19.5% .......................Minimum Required by Law 17% ..........................Breathing Becomes Faster & Deeper 16% ..........................Pilot Light Extinguishes 16-13% .....................Dizziness, Rapid Pulse, Headache, etc. 9% ............................Unconsciousness 6% ............................Convulsions and Death

9. Low barometer • High CO2 • Low O2

10. Stable Isotope Geochemistry • Isotopic ranges of natural gases are large in range, specific, predictable, and capable of providing diagnostic information on their source. • Differences in isotopic mass lead to subtle but significant differences in the behavior of an element during natural processes (fractionation) •  13CO2 = Rsample – Rstandard * 1000 (permil)

12. Possible Carbonate Sources

14. CO2 Contamination Problem in Northwestern Pennsylvania Bailey residence, Volant, Lawrence County 2006 • CO2 ambient levels up to 3.0% measured inside the home • Home was built on about 110 feet of mine spoil from a large surface mine operation of the Brookville and Kittanning seams of the Potsville Fm. • Carbonate source identified as glacial till and the spoil augmented with scrubber sludge

15. Bailey site

16. Aerial View of Bailey • Older project sites • Un-mined land • Bailey Property

17. Bailey Property

18. Bailey Basement floor Plan

19. Bailey Plan SSPP (Radon System)

20. Bailey Plan, Air Exchanger

21. Bailey Elevation

22. Cost / Benefits • Cost: $23,000 • Construction Period: 15 Days • Power: 350watts & Long-term Maintenance • Noise & Temperature differential in basement • Reduce CO2 to 0.08% except very low Barometer

23. CO2 Contamination Problem in Southwestern Pennsylvania Popson residence, Fairchance, Fayette County 2006 • CO2 ambient levels up to 6.3%, exceeded 25% in foundation cracks • The full basement, no windows and partially finished. • Mine 40-60 deep in Redstone Coal, Spoil associated with a massive Limestone seam.

24. Popson Location

25. Popson Property

26. Popson SSPP system

27. Popson Construction Photos Vents SSPP inlet location & restored floor Air inlets for SSPP & Air Exchanger

28. Cost / Benefits • Cost: $27,000 • Construction Period: 20 Days • Problems with working around the partially finished basement • Mine abandoned in interim period, almost did not qualify for AML funds. • Problem may be area wide.

29. CO2 Contamination Problem in Southwestern Indiana Hudson residence, Velpen, Pike County 2008 • O2 levels depressed as low as 12% inside the home • CO2 levels more than 25% measured in cracks and holes in the foundation around the home • Resulted in death of two family cats • Low barometric pressure and heavy rains

30. Post Bond Permit Area Hudson Property

31. Hudson Property

32. Problems at Hudson's

33. Hudson's Conclusion • Monitoring shows less severe in the summer • Modifications or replacement of the basement floor would be required for mitigation. • Sealing of the block walls would require replacing much of the basement already finished and or deep excavation around the perimeter of the home. • USGS has been acquired by the INDNR to help study and recommend solutions.

34. Review • Problems are more extensive • Mostly recently abandoned surface mines • Must have carbonate materials and other conditions to harbor the CO2. • Property owners, developers and local agencies are unaware of the problem.

35. Current Solutions • Sub-Slab Positive Pressure systems, Sealing foundation • Foundation ventilation, French Drains may be required • Air Exchangers may be required on worse case situations.

36. Proposed solutions • Trenching and drainage around property • Land Use / Building Code • Mine regulation

37. Questions • How does topography and compaction of the mine play to the problem? • Do we need to reconsider augmentation of the mine spoil to neutralize AMD? • Should we continue to burden the homeowner with mitigation systems? • Regulation Changes? • Is the problem hiding in your state?