“Blackdamp”

“Blackdamp”

• “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

0.03 ....................................... Normal Air & 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.

O2 - Percent Effect

• 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

Isotopic ranges of natural gases are large in range, specific, predictable, and capable of providing diagnostic information on their source.

• 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)

Bailey residence, Volant, Lawrence County 2006

• 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

Cost: $23,000

• 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

Popson residence, Fairchance,

• 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.

Cost: $27,000

• 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.

Hudson residence,

• 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

Monitoring shows less severe in the summer

• 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.

Problems are more extensive

• 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.

Sub-Slab Positive Pressure systems, Sealing foundation

• Sub-Slab Positive Pressure systems, Sealing foundation

• Foundation ventilation, French Drains may be required

• Air Exchangers may be required on worse case situations.

Trenching and drainage around property

• Trenching and drainage around property

• Land Use / Building Code

• Mine regulation

How does topography and compaction of the mine play to the problem?

• 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?