Changes in the Centralia Coal Fire over Forty

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

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.

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

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.

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.

• 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.

• These coal beds resemble a series of concentric bowls separated from one another by 10 to 100 meters of shale and sandstone. • Beds dip 22 o 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.

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.

• 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 reexamined 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.

• 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.

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.

• 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.

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.

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.

• 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.

Thank You!!!