Changes in the Centralia Coal Fire over Forty Years

1. Changes in the Centralia Coal Fire over Forty Years Melissa A. Nolter and Dr. Daniel H. Vice

2. Introduction • Anthracite coal mining region of Northeast Pennsylvania. • The mine fire began in May of 1962. • The town burned a garbage dump and in the process set the Buck Mountain coal vein on fire. • Mines closed in August of 1962 because of carbon monoxide. • Attracted peak media attention in the late 1970’s and early 1980’s but has received little attention since.

4. Attempts to Fight the Fire • Flushing with water-rock slurry • Fly ash barriers • Trenching • These all failed because of insufficient material and extensive fracturing of the coal and bedrock. • Local politics also hindered fire control

5. A community displaced • The state of Pennsylvania decided to buy out the nearly 1000 residents and permit the fire to burn, uncontrolled. • Some residents refused to leave and today less than 15 people reside in Centralia.

7. Geologic Setting in Centralia • Located in the Valley and Ridge Province. • Is part of the Western Middle Field. • The Western Middle Field consists of a complex series of east-west trending asymmetric synclines and anticlines. A series of anticlines and synclines divide the field into six major basins.

8. Coal is contained in the Pottsville and Lewellyn formation. • Formations consist of conglomerate, sandstone, siltstone, claystone, and shale. • 33 coal beds occur in the Llewellyn Formation, only the lowest four beds are in the Centralia area.

9. These coal beds resemble a series of concentric bowls separated from one another by 10 to 100 meters of shale and sandstone. • Beds dip 22o north on the south limb of the Centralia syncline. • The Buck Mountain bed outcrops close to the southern margin of the Centralia syncline. • Regional folding has fractured both the coal and rock, permitting air access to the subsurface.

10. Description of the Mine Fire • Began on the north limb of the Locust Mountain anticline in the Buck Mountain coal bed. • It advanced in four directions, or fronts. • First front advanced west past St. Ignatius Cemetery towards Mt. Carmel. • Second front advanced southwest and crossed PA Route 61. • Third front advanced south-southeast through Brynesville. • Fourth front advanced east towards Big Mine Run.

12. Evidence for an active front includes gas issuing from vents, warm ground, absence of vegetation, snow melt around vents, mineral deposition and baked rock adjacent to vents. • Measured temperatures of 450˚C, an irreversible mineralogical change occurs in clay. Temperatures we obtained are in that range. • Using remote sensing data and compass and pace methods, we determined the location of and re-examined the fronts. • The cemetery front has advanced at an average of 19 m/year. This compares with an average of 23 m/year observed by the Pennsylvania Department of Environmental Protection.

13. Snowmelt, steam, gases and subsidence were present at the second front indicating that it is still active. • Third front appears to be inactive at this time. there is no gas emission, steam, or visible effect on vegetation. • The fourth front appears to be weakly active because steam emissions are visible and there is no apparent effect on vegetation in that area.

17. Geology’s Impact on the Fire • Coal fires are suppressed by starving them of air, cooling the coal below its ignition point, and forming a barrier to prevent advancement. • The Centralia fire has been difficult to control due to the geology, previous mining, and cultural factors. • In addition to leading the fire deeper into the ground, the dip of the beds served to form a “self-propagating” convection cell between the fire and the incoming air. • A 1983 study shows that these convection cells provide the fire with air and allow it to propagate both laterally and down dip.

21. Extensive fracturing of the coal and bedrock makes surface sealing a difficult method for control because of the inability to locate all openings. • Fractured bedrock makes it difficult to cool the coal with water because these fractures can lead the water away from the fire. • The problem with using fly ash to form a barrier was that the fractured coal and bedrock prevented getting a complete seal, insufficient material was also used.

22. Other reasons • A number of non-scientific factors also hindered efforts at control. • One was cultural heritage, people in the anthracite region mistrust authority. • Other problems included an uncoordinated response, dealing with several government agencies with overlapping jurisdictions, and the inexperience of local officials in dealing with bureaucrats. • This combination of factors led to a start-stop response in fighting the fire. Federal and state agencies failed to develop an effective plan, because of its location and cost.

23. Conclusion • The fire emits carbon dioxide, carbon monoxide and other gases into the atmosphere while consuming a valuable resource, and prohibiting use of the land. • Minerals condensed from the gas and the gases themselves may have detrimental effects on human health.

25. Centralia is a worst-case scenario for the affect of a coal fire on a community. This fire destroyed the physical structure of an entire town and displaced a community. • After a the buyout there was no attempt to extinguish the fire although it is being monitored. • The two fronts that currently appear to be active will continue to burn for many years.

26. Thank You!!!