Attachment B
TRANSECT AND BOREHOLE DESCRIPTIONS AND LOCATION MAPS
Seismic-Reflection, Electrical-Resistivity-Imaging, and Calibration-Borehole Data-Acquisition
and Analysis Services Broad Top Coalfield, Bedford, Fulton, and Huntingdon Counties, South-Central Pennsylvania
Bureau of Geological Survey
Pennsylvania Department of Conservation and Natural Resources 2019
Note: This attachment contains site descriptions and location maps for five (5) proposed transects
(traverse lines), covering commercial seismic-reflection data, a seismic-reflection survey, and an
electrical-resistivity-imaging survey, and for one (1) proposed calibration air-rotary borehole, situated
in the Broad Top coalfield and vicinity, Bedford, Fulton, and Huntingdon Counties, south-central
Pennsylvania. To assist prospective bidders in understanding the bedrock geology and field conditions
to be encountered, descriptions of the likely geologic formations and rock types to be found cropping
out and in the shallow subsurface (i.e., upper thousand feet) are included. The descriptions
(assessments) are a reasonable attempt by the Department to provide objective geologic information
about the work sites. As such, they should be considered average probable conditions and should not
be considered guarantees.
General Description of Geologic Units
Underlying the proposed work sites are one or more of the following bedrock geologic units, including,
from oldest to youngest, the Upper Devonian and Mississippian Rockwell Formation; the Mississippian
Burgoon Sandstone and Mauch Chunk Formation; and the Pennsylvanian Pottsville, Allegheny, and
Glenshaw Formations. The Rockwell Formation consists of buff, fine- to medium-grained, crossbedded,
argillaceous sandstone, and includes some carbonaceous shale containing marine fossils in part,
sporadic conglomerate beds, and local diamictite. The Burgoon Sandstone is light-gray to buff, medium-
grained, crossbedded sandstone and minor siltstone, and includes conglomerate in places toward the
base; it contains plant fossils and minor, thin coals locally. The Mauch Chunk Formation consists of
grayish-red shale, siltstone, mudstone, sandstone, and some conglomerate; some local nonred zones
occur. The Trough Creek Limestone (Loyalhanna Member) occurs at the base of the Mauch Chunk,
consisting of greenish-gray, crossbedded calcareous sandstone to sandy limestone. The Pottsville
Formation is predominantly gray, fine- to coarse-grained sandstone and quartz-pebble conglomerate,
and much subordinate shale, claystone, siltstone, and coal. Pottsville coals have rarely been mined
commercially in the Broad Top. The Allegheny Formation consists of cyclic sequences of sandstone,
siltstone, shale, limestone, claystone, and coal. The three principal commercial coals mined in the past in
the Broad Top—in ascending order, the Fulton, Barnett, and Kelly—occur in the lower two-thirds of the
Allegheny Formation. The Glenshaw Formation (lower half of the Conemaugh Group) is composed of
cyclic sequences of shale, siltstone, sandstone, redbeds (predominantly mudstones), and thin limestone
and coal; it includes up to four marine shale horizons (zones).
Broad Top Coalfield
The Broad Top coalfield, south-central Pennsylvania, covers about 75 square miles and is situated near
the intersection of Bedford, Fulton, and Huntingdon Counties (Figure 1). It is readily accessible from
Harrisburg and Pittsburgh by the Pennsylvania Turnpike (Interstate 76), at Exit 180, via State Route (SR)
475, SR 655, and SR 913 to Robertsdale; and Exit 161, via US Route (US) 30 and SR 26 to Hopewell (SR
915) or Saxton (SR913). It can also be accessed from State College by I99, at Exit 48, via SR 453, US 22,
and SR 26; and from Altoona by I99, at Exit 23, via SR 36, SR 164, and SR 26. From Huntingdon, it can
also be accessed by SR 26 to SR 994 or to SR 913.
TRANSECT 1
TRANSECT 1, covering a distance of 7 line miles, is situated along SR 994 (Old Plank Road) in Huntingdon
County, extending from the east side of Sideling Hill (east end, Longitude (X) and Latitude (Y)
coordinates X = -78.0441, Y = 40.2074), Saltillo 7.5-minute quadrangle, to 2 miles north of Eagles
Foundry (west end, coordinates X = -78.1126, Y = 40.2606), along Trough Creek Valley, Cassville 7.5-
minute quadrangle, (Figures 1 and 2). The transect crosses State Game Lands 121 around Joller and Rays
Hill. Additionally, the transect extends past PGE Marcellus gas-well properties, Hess Tract (including well
API 37-061-20001-00-00), mostly just west Eagle Foundry, and Shannon Todd Pad A (including well API
37-061-20014-00-00), about 1 mile north of Eagle Foundry and just to the east of SR 994 (Figure 2).
TRANSECT 1 starts (east end) in the Rockwell Formation and continues northwestward, successively
crossing the Burgoon Sandstone (Sideling Hill) and Mauch Chunk Formation, followed by the Pottsville
and Allegheny Formations (Rays Hill area), and terminating (west end) in a broad expanse of the Mauch
Chunk Formation.
TRANSECT 2
TRANSECT 2, covering a distance of 14 line miles, follows SR 913 in Fulton and Huntingdon Counties,
extending from the east side of Sideling Hill (east end, coordinates X = -78.0710, Y = 40.1312), Saltillo
7.5-minute quadrangle, to Terrace Mountain (near East Saxton) (west end, coordinates X = -78.2287, Y =
40.2253), Saxton 7.5-minute quadrangle (Figures 1 and 3). The transect runs just south of State Game
Lands 067 near Barnettstown.
TRANSECT 2 begins (east end) in the Rockwell Formation and proceeds northwestward, crossing the
Burgoon Sandstone (Sideling Hill) and Mauch Chunk Formation, next through areas of the Pottsville and
Allegheny Formations (Robertsdale and Broad Top City areas), then over the Pottsville Formation
(Shoups Run valley), and back again in the Mauch Chunk Formation, then the Burgoon Sandstone and
finishing (west end) in the Rockwell Formation.
Figure 1. Reconnaissance bedrock geologic map of the Broad Top coalfield, showing locations of
TRANSECTS 1, 2, and 3 (labeled red lines) and TRANSECTS 4 and 5 (labeled blue line).
Figure 2. Location map of TRANSECT 1 (red line), along northeastern part of the Broad Top coalfield in
Huntingdon County. Locations of Marcellus gas wells indicated by black arrows.
Figure 3. Location map of TRANSECT 2 (red line), crossing northern part of the Broad Top coalfield in
Fulton and Huntingdon Counties.
TRANSECT 3
TRANSECT 3, covering a distance of 10 line miles, runs along SR 915 in Bedford County, extending from
the intersection with Wells Valley Road near Sideling Hill Creek (east end, coordinates X = -78.1386, Y =
40.0764), Wells Tannery 7.5-minute quadrangle, to just west of the intersection of State Route 26
(Raystown Road) and Polecat Hollow Road, west of Hopewell (west end, coordinates X = -78.2779, Y =
40.1409), Hopewell 7.5-minute quadrangle (Figures 1 and 4). The transect crosses locally or passes just
north of State Game Lands 261 near Langdondale and Sandy Run.
TRANSECT 3 commences (east end) in the Mauch Chunk Formation and continues within the unit for
about two-thirds the total distance of the transect. The transect next successively crosses the Pottsville,
Allegheny, and Glenshaw Formations, and then proceeds to continue across the same three units in
reverse order just west of Langdondale within the Sandy Run valley. TRANSECT 3 then crosses the
Mauch Chunk Formation and Burgoon Sandstone, and terminates (west end) in the Rockwell Formation.
Figure 4. Location map of TRANSECT 3 (red line), crossing the southwest corner of the Broad Top
coalfield and adjacent areas in Bedford County.
TRANSECTS 4 and 5
TRANSECTS 4 and 5 coincide, and each covers a distance of 2.5 line miles. They follow a portion of
TRANSECT 1, along SR 994 (Old Plank Road) in Huntingdon County, extending from the hairpin curve just
south of Joller on State Game Lands 121 (east end, coordinates X = -78.0661, Y = 40.2008), Saltillo 7.5-
minute quadrangle, to about 1 mile northwest of crossroads at Cooks (west end, coordinates X = -
78.0984, Y = 40.2232), still within the Saltillo 7.5-minute quadrangle (Figures 1 and 5).
TRANSECTS 4 and 5 begin (east end) in the lower Pottsville Formation along the east side of Rays Hill,
next cross the lower Allegheny Formation toward the crest of the ridge, then continue back into the
Pottsville Formation, and finally terminate in a broad expanse of the Mauch Chunk Formation.
Figure 5. Location map of TRANSECTS 4 and 5 (blue line), following a portion of TRANSECT 1 (Figures 1
and 2), along northeastern part of the Broad Top coalfield in Huntingdon County.
Calibration Borehole (HUN061_0661)
A calibration borehole, designated HUN061_0661, will be drilled along Rays Hill on State Game Lands
121, at the primary (preferred) location just south of SR 994 (coordinates X = -78.0729, Y = 40.2055),
Saltillo 7.5-minute quadrangle (Figures 1 and 6). In the unlikely event the primary location proves to be
unsatisfactory at or before the time of mobilization, the borehole will be drilled at the secondary
(backup) location, 0.35 mile north of the primary location. The anticipated total depth of the proposed
borehole is 500 feet.
Borehole HUN061_0661 will commence in the lower Allegheny Formation, about 40 feet or less above
the Barnett coal, which is about 5 feet thick and extensively deep mined along Rays Hill in the past.
Occurring about 50 feet below the Barnett is the Fulton coal, which is about 5 feet thick and also deep
mined in the area in the past. Based on available underground-mine maps, drilling at the primary
location for HUN061_0661 is not likely to encounter the old Barnett workings, and it is also believed that
the site will be considerably west of the known limits of old Fulton mine workings. Therefore, drilling will
probably not encounter old deep-mine workings, but at most only one (1) mine void. The base of the
Allegheny Formation is traditionally placed about 20 to 30 feet below the Fulton, so that the total
thickness for the Allegheny here is about 120 feet. Immediately underlying the Allegheny is the Pottsville
Figure 6. Location map of proposed Borehole HUN061_0661, showing both primary (preferred) and
secondary (backup) sites (blue circles) near SR 994, on Pennsylvania State Game Lands 121, Rays Hill, in
northeastern part of the Broad Top coalfield, Huntingdon County.
Formation, which here is on the order of 180 feet thick. Although some of the Pottsville sandstones may
be well cemented and hard, past drilling in the Broad Top coalfield indicates that they cut well with air-
rotary drilling. The borehole will finish in the Mauch Chunk Formation, which underlies the Pottsville.
Drilling is expected to penetrate about 200 feet of Mauch Chunk Formation, although the contact with
the Pottsville may be difficult to discern, as non-red Mauch Chunk sandstones occur locally toward the
top of the formation and may not be readily distinguishable from Pottsville sandstones.