Pioneer Tunnel in Ashland, Pennsylvania is a tourist site that allows examination of an old anthracite strip mine and underground anthracite coal workings in Mahanoy Mountain.  The surface strip mine and the underground mine exploited anthracite coal beds in the Llewellyn Formation (middle Desmoinesian Series, upper Middle Pennsylvanian), as did numerous mines in eastern Pennsylvania's coal fields.


Mammoth Vein Stripping - partially overgrown surface strip mine on Mahanoy Mountain that exploited the northward-dipping Mammoth Coal bed (lower Llewellyn Formation, Desmoinesian Stage, upper Middle Pennsylvanian).  Looking WSW.



Ashland Mountain, looking E.  This ridge is a continuation of the Mahanoy Mountain ridge (behind the camera).  The gap in the foreground is where Mahanoy Creek lies.  Northward-dipping rocks of the Llewellyn Formation make up most of both the Ashland Mt. & Mahanoy Mt. ridges.



Mahanoy Mountain cross-section, looking W, showing steeply tilted, northward-dipping rocks of the Llewellyn Formation.  This is the southern limb of the Shamokin Syncline.  The surface strip mines exploited the thickest anthracite beds in the section - the Mammoth Coal (left) and the Primrose Coal (right).  The underground mine principally exploited the Orchard, Primrose, Mammoth, Seven Foot, and Buck Mountain Coals.  The yellowish-colored beds on the cross-section are supposed to indicate siliciclastic rocks (shales, siltstones, sandstones).




Pioneer Tunnel - modern tourist entrance to old Pioneer Tunnel Coal Mine, which operated from the 1910s to the 1930s.  Anthracite coal was hauled out by rail to the eastern end of Mahanoy Mountain, where it was dumped down a chute to a breaker for processing and shipping.


Pioneer Tunnel Coal Mine, looking S - near southern end of main tunnel, at the top of the Pottsville Formation, just below the base of the Llewellyn Formation.  The Little Buck Mountain Coal bed is indicated by the small white sign.  It is the top-most coal bed in the Pottsville.  Near the end of this mine's commercial activities, a tunnel was driven further south & a gangway was developed along the Lykens Valley No. 1 Coal in the Pottsville Formation's Schuylkill Member (upper Atokan Series, lower Middle Pennsylvanian).  The Lykens Coal was the stratigraphically deepest unit exploited here.



Pioneer Tunnel Coal Mine, looking W.  This is the Buck Mountain Gangway, developed along strike at the Buck Mountain Coal bed, at the very base of the Llewellyn Formation.  The rock wall hanging over the tourists' heads at upper right is the upper bedding plane of the mined-out Buck Mountain Coal.  The tilt of this bedding plane is representative of the dip angle of all the rocks in this mine.



Mammoth Coal, looking E - northward dipping (tilted to the left) anthracite coal of the Mammoth Coal bed, in the lower Llewellyn Formation.  The Mammoth is the thickest anthracite bed in the entire world.  It has been extensively mined throughout eastern Pennsylvania's anthracite coal fields.  At many localities, it is a succession of three separate coal beds (three “splits” - Bottom Split, Middle Split, and Upper Split), separated by fine-grained to coarse-grained siliciclastics.  Where the Mammoth Coal is one unit, it can be up to 50' thick.  Structural doubling & tectonic flow can make the Mammoth Coal appear even thicker in some places.



Mammoth Coal - anthracite coal sample (12.4 cm across) from the Mammoth Coal bed.  Collected from exposure shown above, along the walls of the main tunnel.  Collected & generously donated by Pioneer Tunnel Coal Mine staff.



Anthracite Coal - large block on public display at Pioneer Tunnel Coal Mine.


Anthracite Coal - large block on public display at Pioneer Tunnel Coal Mine.  This material is ~90% carbon.


Anthracite Coal - large block on public display at Pioneer Tunnel Coal Mine.



Fossil log (probably a tree fern, either permineralized or a cast) in basal siliciclastic beds of the Llewellyn Formation (upper Middle Pennsylvanian).  It's exposed in the hanging wall of the Buck Mountain Gangway.


Fossil logs (carbonized compressions) in basal siliciclastic beds of the Llewellyn Formation.  Hanging wall exposure along the the Buck Mountain Gangway.


Fossil lycopod log (carbonized compression) in basal siliciclastics of the Llewellyn Formation.  Hanging wall exposure along the Buck Mountain Gangway.


Fossil tree trunk (preserved as a cast) from the Llewellyn Formation at Pioneer Tunnel Coal Mine.



Some info. from:


Ermert, E.R.  1994.  The Story of Pioneer Tunnel Coal Mine & Steam Train.  14 pp.


Edmunds, W.E., V.W. Skema & N.K. Flint.  1999.  Stratigraphy and sedimentary tectonics, Pennsylvanian.  in  The geology of Pennsylvania.  Pennsylvania Geological Survey Special Publication 1: 148-169.



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