Preliminary Estimate of Coal Resources in the Gillette

Coalfield Affected by the Location of the Burlington

Northern/Union Pacific Joint Mainline Railroad

Open-File Report 2006-1206

U.S. Department of the Interior

U.S. Geological Survey
Preliminary Estimate of Coal Resources in the Gillette 

Coalfield Affected by the Location of the Burlington 

Northern/Union Pacific Joint Mainline Railroad

By Timothy J. Rohrbacher, Jon E. Haacke, David C. Scott, Lee M. Osmonson, and James A. Luppens

Open-File Report 2006-1206

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

U.S. Geological Survey, Reston, Virginia: 2006

Posted online July 2006

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Suggested citation:

Rohrbacher, T.J., Haacke, J.E., Scott, D.C. Osmonson, L.M., and Luppens, J.A. 2006, Preliminary estimate of coal 

resources in the Gillette coalfield affected by the location of the Burlington Northern/Union Pacific joint mainline railroad: U.S. Geological Survey Open-File Report 2006-1206, 16 p.
Contents

Summary..........................................................................................................................................................................................................................................1

References Cited..........................................................................................................................................................................................................................16

Figures

1. Burlington Northern/Union Pacific joint mainline rail service to the southern and middle mining areas (pods) of the Gillette coalfield.

This photo of a unit coal train headed south was taken at the junction of the joint mainline and State Highway 450 overpass,

where the Jacobs Ranch Mine and Black Thunder Mine rail loops enter the joint mainline.................................................................................2

2. In late 2004 the U.S. Geological Survey began a new assessment of the Gillette coalfield stratigraphy using information from

many of the new coalbed methane wells that had been drilled. Coal bed correlations were modified and major mining restraints

identified (Luppens, 2006). A status report was presented at the Bureau of Land Management’s Regional Coal Team meeting in

Casper, Wyoming on April 19, 2006 by the senior author.............................................................................................................................................3

3. The preliminary interpretation of new data provided by recent coalbed methane exploration and development has resulted in

significant changes to coal bed correlations in the Gillette coalfield. Using the newly developed geological

models and pit designs presently being used in the southern and middle mining areas (pods), tonnage estimates were calculated

for recoverable coal resources (the true footprint of the surface rights-of-way) that would be affected by the present location

of the Burlington Northern/Union Pacific joint mainline. That footprint contains more than 1.8 billion short tons of in-place resources .........4

4. Map showing the infrastructure: highways, railroads, towns, and mine locations in the Gillette coalfield area. Also shown are

the geologic pods (mining areas), data location points, a portion of the paleo-Powder River channel, 500-ft-depth isopach to the

top of minable coal, and the Burlington Northern/Union Pacific joint mainline location. The coal stratigraphy and coal quality

are similar within each individual pod. CBM, coalbed methane................................................................................................................................5

5. Preliminary isopach map of the Anderson coal bed, which is the most important coal bed in the Gillette coalfield. It averages

more than 50 ft thick and has a maximum thickness of greater than 250 ft north of Wright, WY. The bed is truncated to the west

by the paleo-Powder River stream channel and shows the effects of at least three large east-west stream channels. Note that

the thickest part of the resource is immediately west of the Burlington Northern/Union Pacific joint mainline railroad....................................6

6. Preliminary isopach map of the Canyon coal bed, which is the second most important coal bed in the middle and southern

pods of the Gillette coalfield and lies below the Anderson coal bed. It averages more than 30 ft thick and has a maximum

thickness greater than 150 ft north of Gillette, Wyoming. In much of the middle and southern pod area, the Canyon coal bed

coalesces with the Anderson bed and is then referred to as the Anderson coal bed ............................................................................................ 7
7. Preliminary Anderson coal bed isopach map for the middle and southern pods of the Gillette coalfield with north-south and

east-west cross sections, mines, and area infrastructure locations. The thickest portion of the Anderson coal bed deposit lies

west of the Burlington Northern/Union Pacific (BN/UP) joint mainline (in blue) from T42-T45N and R71-R74W..................................................8

8. Stratigraphic cross section incorporating information from wells drilled into the Anderson and Canyon coal beds along the

joint mainline of the Burlington Northern/Union Pacific railroad. The section extends north to south across the middle and

southern pods of minable coal resources in the Gillette coalfield. The average depth to the top of the Anderson coal bed and

the average thickness of minable coal were determined from these coalbed methane and oil wells along the railroad rights-of-way

(ROW) and substantiated by seven stratigraphic sections (locations only shown) drawn perpendicular to the joint mainline railroad

right-of-way. Green color, Anderson coal bed; light blue, Canyon coal bed; dark blue, Smith coal bed; red, Felix coal bed; orange,

burned zone. Coal is shown as black ...........................................................................................................................................................................9

9. This east-west cross-section across the Burlington Northern/Union Pacific joint mainline was designed using the average coal

and overburden thicknesses (shown above) from the north-south stratigraphic section shown in figure 8 and from the mine

planning parameters obtained from truck-shovel/dragline mines in the middle and southern pods. An average coal density of

1,770 tons/ac-ft (Wood, 1983, Fort Union Assessement Team, 1999) was obtained from U.S. Geological Survey coal quality data.

Mining parameters used in the cross-section design are listed on the following slide. ROW, right-of-way.......................................................10

10. Generalized pit design parameters used for the surface mine pits east and west of the joint mainline railroad rights-of-way

(RR ROW) shown in figure 9. DL, dragline; TS, truck-shovel ....................................................................................................................................11

11. Calculations used to estimate the coal resources affected by the Burlington Northern/Union Pacific joint mainline railroad in

the middle and southern pods of the Gillette coalfield and their value shown here using a coal market sales price for the

southern Gillette coalfield quoted on April 17, 2006. Cf, cubic feet; ac-ft, acre feet; sf/ac, square feet per acre...............................................12

12. Estimated recoverable coal resources affected by the Burlington Northern/Union Pacific joint mainline railroad and the

potential mining tax revenues from those resources ...............................................................................................................................................13

13. Some general challenges that face the coal mining industry as they plan to develop the resources west of the Burlington

Northern/Union Pacific joint mainline railroad. BCY, bank cubic feet. ................................................................................................................... 14

14. Surface restrictions to mining are generally thought to carry a small footprint or affect an area related to the surface expression.

With the 450 ft of track and access road rights-of-way (ROW) required by the Burlington Northern/Union Pacific (BN/UP) joint

mainline operation, the footprint on the coal resource, an average of 361 ft below ground level, is nearly 8 times the surface

reflection – without additional safety berms and benches that may be required..................................................................................................15
Preliminary Estimate of Coal Resources in the Gillette 

Coalfield Affected by the Location of the Burlington 

Northern/Union Pacific Joint Mainline Railroad

By Timothy J. Rohrbacher, Jon E. Haacke1, David C. Scott1, Lee M. Osmonson1, and James A. Luppens



 Denver, CO.



 Reston, VA.

Summary

This publication, primarily in graphic form, presents a 

preliminary resource assessment related to a major, near-term 

restriction to mining in that portion of the Gillette coalfield, 

Wyoming, that is traversed by the Burlington Northern/Union 

Pacific joint mainline railroad. This assessment is part of a 

current Powder River Basin regional coal assessment, including 

both resources and reserves, being conducted by the U.S. 

Geological Survey. The slides were used to illustrate a presentation of study results at a meeting of the Bureau of Land 

Management’s Regional Coal Team in Casper, Wyoming on 

April 19, 2006 by the senior author.

Geologic and drilling data indicate that significant volumes of low sulfur coal resources may be bypassed by mining 

operations during the next 10 to 12 years. The effective footprint of the unrecoverable coal resources under the railroad 

corridor is much larger than previously estimated when practical mining geotechnical and safety offsets are considered. For 

example, the box cut required to open the coal resources west 

of the railroad right-of-way could have an effective mining 

ratio of greater than 45 to 1 (bank cubic yards overburden to 

recoverable tons of coal).

It is estimated that 1.7 billion short tons of recoverable 

coal are impacted by the 35 miles of railroad and associated 

access road right-of-ways. That recoverable resource represents 

potential Federal and State tax revenue of approximately $8.6 

billion dollars based on current (April 17, 2006) coal prices.
Figure 1. Burlington Northern/Union Pacific joint mainline rail service to the southern and middle mining areas (pods) of the Gillette coalfield. 

This photo of a unit coal train headed south was taken at the junction of the joint mainline and State Highway 450 overpass, where the Jacobs 

Ranch Mine and Black Thunder Mine rail loops enter the joint mainline.

 Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 2. In late 2004 the U.S. Geological Survey began a new assessment of the Gillette coalfield stratigraphy using information from many of 

the new coalbed methane wells that had been drilled. Coal bed correlations were modified and major mining restraints identified (Luppens, 2006). 

A status report was presented at the Bureau of Land Management’s Regional Coal Team meeting in Casper, Wyoming on April 19, 2006 by the 

senior author.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 
Figure 3. The preliminary interpretation of new data provided by recent coalbed methane exploration and development has resulted in 

significant changes to coal bed correlations in the Gillette coalfield (Luppens and others, 2006). Using the newly developed geological models 

and pit designs presently being used in the southern and middle mining areas (pods), tonnage estimates were calculated for recoverable coal 

resources (the true footprint of the surface rights-of-way) that would be affected by the present location of the Burlington Northern/Union Pacific 

joint mainline. That footprint contains more than 1.8 billion short tons of in-place resources.

 Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 4. Map showing the infrastructure: highways, railroads, towns, and mine locations in the Gillette coalfield area. Also shown are the 

geologic pods (mining areas), data location points, a portion of the paleo-Powder River channel, 500-ft-depth isopach to the top of minable coal, 

and the Burlington Northern/Union Pacific joint mainline location. The coal stratigraphy and coal quality are similar within each individual pod. 

CBM, coalbed methane.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 
Figure 5. Preliminary isopach map of the Anderson coal bed, which is the most important coal bed in the Gillette coalfield. It averages more than 

50 ft thick and has a maximum thickness of greater than 250 ft north of Wright, WY. The bed is truncated to the west by the paleo-Powder River 

stream channel and shows the effects of at least three large east-west stream channels. Note that the thickest part of the resource is immediately 

west of the Burlington Northern/Union Pacific joint mainline railroad.

 Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 6. Preliminary isopach map of the Canyon coal bed, which is the second most important coal bed in the middle and southern pods of the 

Gillette coalfield and lies below the Anderson coal bed. It averages more than 30 ft thick and has a maximum thickness greater than 150 ft north 

of Gillette, Wyoming. In much of the middle and southern pod area, the Canyon coal bed coalesces with the Anderson bed and is then referred to 

as the Anderson coal bed.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 
Figure 7. Preliminary Anderson coal bed isopach map for the middle and southern pods of the Gillette coalfield with north-south and eastwest cross sections, mines, and area infrastructure locations. The thickest portion of the Anderson coal bed deposit lies west of the Burlington 

Northern/Union Pacific (BN/UP) joint mainline (in blue) from T42-T45N and R71-R74W.

 Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 8. Stratigraphic cross section incorporating information from wells drilled into the Anderson and Canyon coal beds along the joint 

mainline of the Burlington Northern/Union Pacific railroad. The section extends north to south across the middle and southern pods of minable 

coal resources in the Gillette coalfield. The average depth to the top of the Anderson coal bed and the average thickness of minable coal were 

determined from these coalbed methane and oil wells along the railroad rights-of-way (ROW) and substantiated by seven stratigraphic sections 

(locations only shown) drawn perpendicular to the joint mainline railroad right-of-way. Green color, Anderson coal bed; light blue, Canyon coal 

bed; dark blue, Smith coal bed; red, Felix coal bed; orange, burned zone. Coal is shown as black.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 
Figure 9. This east-west cross-section across the Burlington Northern/Union Pacific joint mainline was designed using the average coal and 

overburden thicknesses (shown above) from the north-south stratigraphic section shown in figure 8 and from the mine planning parameters 

obtained from truck-shovel/dragline mines in the middle and southern pods. An average coal density of 1,770 tons/ac-ft (Wood and others, 1983; 

Fort Union Assessment Team, 1999) was obtained from U.S. Geological Survey coal quality data. Mining parameters used in the cross-section 

design are listed on the following slide. ROW, right-of-way.

10 Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 10. Generalized pit design parameters used for the surface mine pits east and west of the joint mainline railroad rights-of-way (RR ROW) 

shown in figure 9. DL, dragline; TS, truck-shovel.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 11
Figure 11. Calculations used to estimate the coal resources affected by the Burlington Northern/Union Pacific joint mainline railroad in the 

middle and southern pods of the Gillette coalfield and their value shown here using a coal market sales price for the southern Gillette coalfield 

quoted on April 17, 2006. Cf, cubic feet; ac-ft, acre-feet; sf/ac, square feet per acre.

12  Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 12. Estimated recoverable coal resources affected by the Burlington Northern/Union Pacific joint mainline railroad and the potential 

mining tax revenues from those resources.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 13
Figure 13. Some general challenges that face the coal mining industry as they plan to develop the resources west of the Burlington Northern/Union 

Pacific joint mainline railroad. BCY, bank cubic feet.

14  Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad
Figure 14. Surface restrictions to mining are generally thought to carry a small footprint or affect an area related to the surface expression. 

With the 450 ft of track and access road rights-of-way (ROW) required by the Burlington Northern/Union Pacific (BN/UP) joint mainline operation, 

the footprint on the coal resource, an average of 361 ft below ground level, is nearly 8 times the surface reflection – without additional safety 

berms and benches that may be required.

Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad 15
References Cited

Ellis, M.S., Molnia, C.L., Osmonson, L.M., Ochs, A.M., Rohrbacher, T.J., Mercier, Tracey, and Roberts, L.N.R., 2002, 

Evaluation of economically extractable coal resources in 

the Gillette Coalfield, Powder River Basin, Wyoming: U.S. 

Geological Survey Open-File Report 2002-180, http://pubs.

usgs.gov/of/2002/ofr-02-0180.

Fort Union Coal Assessment Team, 1999, 1999 Resource 

assessment of selected Tertiary coal beds and zones in the 

Northern Rocky Mountains and Great Plains Region: U.S. 

Geological Survey Professional Paper 1625-A, 2 CDROMs.

Luppens, J.A., Rohrbacher, T.J., Haacke, J.E., Scott, D.C., 

and Osmonson, L.M., 2006, Status Report: USGS Coal 

Assessment of the Powder River, Wyoming: U.S. Geological Survey Open-File Report 2006-1072, http://pubs.usgs.

gov/of/2006/1072/.

National Coal Council, 2006, Coal: America’s Energy Future: 

National Coal Council, Thomas G. Kraemer, chair, v. 1, 

125 p.

Platts, 2006, Coal Outlook: 3333 Walnut Street, Boulder, CO, 

v. 30, No. 16, http://www.platts.com.

Wood, G.H., Jr., Kehn, T.M., Carter, M.D., and Culbertson, 

W.C., 1983, Coal resource classification system of the U.S. 

Geological Survey: U.S. Geological Survey Circular 891, 

65 p.

16  Preliminary Estimate of Coal Resources in the Gillette Coalfield Affected by the Location of the BN/UP Railroad