Rt. 61 in eastern Pennsylvania runs through some hilly coal country.  In the Western Middle Anthracite Field, east of Shamokin and Mount Carmel, the road goes through the ghost town of Centralia - one of the stranger sights in eastern America.  Just south of Centralia, Rt. 61 takes a sharp turn at a mound of debris (see below).  The modern road bypasses what used to be a newly paved road out of Centralia.  Kinda strange.




At the other end of the blocked stretch of road, the following sign has been posted by the Pennsylvania highway department.  Really kinda strange!




One can walk along the abandoned stretch of road.  The asphalt is buckled, bowed, cracked, fissured, and smoking.  Centralia, Pennsylvania is a famous place for observing the effects of an underground coal fire.  The fire started in late May 1962.  Several stories are around that purport to explain the start of the fire.  The most plausible is that the fire was accidentally set by firemen hired by town officials - they were burning garbage in the town dump to increase space (or to diminish foul odors), in preparation for an upcoming holiday (Memorial Day).  An exposed coal bed was ignited, and it's been burning ever since.  It'll burn forever (as long as the coal seam exists).


Centralia Underground Coal Fire - subsidence has destroyed former Rt. 61.  The photo above & below are what the road looked like in fall 2000 (Kent State University geology majors for scale).



Centralia Underground Coal Fire - this is what the same stretch of road looked like in summer 2006 (above & below).  The main fissure down the center of the road has noticeably widened (Ohio State University at Newark geologist & biologist for scale).  Looking ~SW.



A major, expensive operation was undertaken to extinguish the coal fire.  A huge trench was dug just south of town.  Officials hoped to intercept & dig out the offending coal seam before the fire spread too far.  The interception trench project failed to put out the fire.


Centralia Interception Trench as it looked in fall 2000.  Looking WSW.


Centralia Interception Trench as it looked in summer 2006.  Looking NE.



The coal bed that's on fire is the Buck Mountain Coal (aka No. 5 Coal), at the base of the Llewellyn Formation.  The bed defines the stratigraphic contact between the Llewellyn Fm. and the underlying Pottsville Formation.  Anthracite and sub-anthracite coal beds of the Llewellyn Formation have tremendous economic significance in eastern Pennsylvania.  The most important coal interval in the Llewellyn is the Mammoth Coal Zone (aka No. 8 Coal, No. 8˝ Coal, and No. 9 Coal).


Age of Buck Mountain Coal: mid-Desmoinesian Stage, upper Middle Pennsylvanian.



Centralia Underground Coal Fire - heat from the burning coal bed has killed these trees along the failed interception trench.  Some have been scorched black.



Centralia Underground Coal Fire - smoking vents have been and still are common along the walls of the interception trench.  Unusual minerals litter the ground in the vicinity of the vents.


Centralia Underground Coal Fire - another vent area.



Several minerals occur in the Centralia Interception Trench.  Some are unidentified.  Identified minerals include native sulfur (S), tschermigite ((NH4)Al(SO4)2·12H2O) & apjohnite (MnAl2(SO4)4·22H2O); the latter two minerals are very rare.  The above photo shows several rocks & burned wood with encrusting sulfur crystals (yellow).  The white specimens may be tschermigite and/or apjohnite.  I don't know what the red stuff is.  Many of these specimens were quite hot when collected.  My students laughed at me for wearing oven mitts at this locality, but they soon realized why.


Unidentified red sulfur-bearing mineral from coal fire vent at Centralia Interception Trench.



Burned wood with encrusting sulfur crystals, from the Centralia Interception Trench.  How does the sulfur form?  The coal bed has a minor component of sulfur (in the form of sulfide minerals, sulfate minerals, or S-bearing organic matter).  The rod-shaped, flagellated, hydrogen-scavenging proteobacterium Desulfovibrio desulfuricans (Beijerinck, 1895) can convert sulfate minerals into hydrogen sulfide gas (H2S).  When released at the surface, the hydrogen sulfide gas oxidizes, and sulfur crystals form.



Seeing the ground on fire is something one doesn't quickly forget.



Some mineral info. provided by Matt Livingood, Jason Winicaties, and Jared Stein.





The underground coal fire at Centralia started in 1962.  For many years, smoke & fumes have risen from yards, streets, and people's basements.  Folks started moving out in the late 1960s.  Attempts to put out the fire failed.


In early 1981, a smoking sinkhole formed underneath a young boy, and he sank down to his waist.  He tried wriggling out, but a larger, deeper hole formed around him.  He hung on to plant roots at about 3' down to keep from falling further.  His cousin was yards away, and came to his rescue.  The smoke was so dense that the cousin could barely see the kid's red cap only three feet down.  He grabbed blindly into the hole & dragged the boy out.


Most Centralia families left after this incident, which made national headlines.  Centralia is now a ghost town - the last Centralia residents left in early 2010.  Before then, an occasional standing house could still be seen in “town”.


Centralia now consists of abandoned, overgrown streets and alleyways, with sidewalks and front steps leading nowhere.








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