Project Name: Preservation of Eagle Rock at the Rosebud Mine Research Surveying Start Date: 1978 Mining and Reclamation Start Date: 1989 Project End Date: Monitoring of bird habitat is ongoing. Location: The Rosebud Mine, owned and operated by Western Energy Company (WECo), is located in Colstrip, Montana in Rosebud County (Southeastern Montana). This reclamation project was conducted in Area C under Permit No. SMP 85003C.

Eagle Rock in Colstrip Montana Prior to Mining and Reclamation Efforts

Project Specialists: Bruce Waage, Senior Scientific Specialist (Wildlife)
Peter Martin, Senior Scientific Specialist (Vegetation)

History of Mine: Western Energy Company (WECo), a surface coal mining subsidiary of Montana Power Company, operates the Rosebud Mine adjacent to the town of Colstrip in Southeastern Montana. The town of Colstrip was founded in 1923 by the Northern Pacific (NP) Railroad. Coal mined there from 1923 to 1958 was used to power NP railroad locomotives. Northern Pacific became a part of Burlington Northern Railroad and in 1958, when all locomotives were switched to diesel fuel, coal mining ceased at Colstrip. Ten years later Montana Power Company (MPC) purchased the Colstrip project and expanded the mine to provide coal for electrical generation. WECo was created in 1968 to mine the coal reserves.

Western Energy Company (WECo), adhering to state and federal laws, conducted numerous environmental surveys in order to obtain mining permits. Annual surveys were conducted to gather environmental information on air quality, surface and ground water, soils, vegetation, wildlife and archeology. Data was gathered by in-house staff and or contracted out to consultants.

In 1978, a wildlife survey conducted to assess wildlife values of a future mine permit revealed that a large sandstone outcrop complex locally known as Eagle Rock did indeed contain an active Golden Eagle nest. Emphasis was placed on how this unique feature, located within the middle of a coal reserve, could be maintained. This large prominent sandstone outcrop had aesthetic value and contained an archeological site known as Farley Lookout. Farley Lookout is interpreted by archeologists to be a temporary lookout and campsite for native peoples. The archeologist based this conclusion on the location of the site and on the variety of stone tools and lithic items found at the site.

Eagle Rock has historically been used by golden eagles, great-horned owls and prairie falcons. A variety of other wildlife, including small mammals and landbirds, have been observed using the outcrop and adjacent habitats. The native vegetation will act as a seed reservoir for the surrounding reclamation.

Reclamation Objectives: Reclamation plans were developed in cooperation with the Montana Department of Environmental Quality that would meet the needs of the mine plan and still retain the important values provided by the outcrop. It was anticipated that the retention of the pre-mine bluff would have a positive impact on the postmine wildlife community. It would complement the reclaimed topography surrounding the outcrop and also retain a natural cliff feature.

Western Energy Company (WECo) received its Area C mine permit in January of 1989. A mine plan had been developed that would leave approximately 6.6 acres encompassing much of the native outcrop. Western Energy Company (WECo) later recognized that an enlargement of the undisturbed island on the north side of Eagle Rock could have additional wildlife benefits and incorporated a bluff extension into the plan. It effectively preserved more native sandstone cliff habitat bringing the exclusion area to 12 acres. The bluff extension plan also elevated a segment of the outcrop making it more prominent and useful for wildlife, particularly raptors. The new bluff extension design effectively added cliff area to replace some cliff features which were lost in the mining process. The mining of the coal reserve was conducted on all sides of Eagle Rock, leaving this large sandstone feature isolated in a large area of reclamation.

Mining Techniques and Construction Narrative: The reclamation of this site entailed special dragline spoil handling and placement as the dragline cast the spoil to the outside or away from the Eagle Rock on three sides causing a tremendous deficit of spoil which needed to be filled. A massive effort by the scraper fleet was required to transport the spoil from considerable distance bringing the postmine topography to an imperceptible match with the Eagle Rock native edge. On the remaining north west side, the dragline had to rehandle the spoil, casting it out and on the return pass casting it back in, to achieve the required fill for the approximate postmine topography.

The blasting of the overburden material immediately surrounding the Eagle Rock required special considerations to prevent shock waves from causing the outcrop to collapse. The outcrop has a complex of finger like buttresses that jut out making them vulnerable to shock from blasting. Furthermore, the outcrop had been isolated on a pedestal on all four sides. A geotechnical analyses refined drilling techniques and a multiple deck blasting sequence was successfully used which kept the rock outcrop intact. This method was used at all locations encircling the outcrop.

Achieving this kind of postmine reclamation feature would have been impossible using normal reclamation and mining procedures. Special planning and effort were necessary to achieve the desired outcome. This reclamation technique enabled WECo to recover as much coal reserve as possible, meet postmine slope stability, improve land use potential for wildlife and reduce mine disturbance.

The following photos show the sequence of events which resulted in a natural looking and aesthetically pleasing landscape.

Eagle Rock prior to disturbance. View looking North	Mining activity advancing around Eagle Rock. View looking North
Highwall around Eagle Rock. View looking North	Gradual backfilling around Eagle Rock. View looking North
Backfilled area at native grade looking North	Dragline scaling northeast end of Bluff Extension. View looking South
Reclamation has advanced on three sides, soiled and seeded. View looking Southwest	Bluff Extension on North side of Eagle Rock. Shows natural bluff and extension created by mining

Results: The implementation of this reclamation plan resulted in:

• Retention of the golden eagle nest. This nest will be available for future nesting activity by the golden eagles, and prairie falcons.
  
• Demonstrated use following mining by American kestrels, great-horned owls (1995, 96, 97), violet green swallows, rock wrens and others.
  
• Retention of the aesthetic values of the sandstone outcrop and bluff extension. The bluff extension on the north face effectively blends with the topography and was additive to the overall success of the value of the outcrop.
  
• Preservation of the Farley Lookout archeological site.

Eagle Rock today - View looking Northwest

Supplemental Narrative: Lessons in mine planning, spoil handling with the dragline and incorporating bluff extensions into a reclamation plan to benefit wildlife and aesthetics could be adapted into other mines with similar reclamation situations.

Eagle Rock is a very visible site which presents a positive image of reclamation and mining to the public. Through numerous photos, and tours, local interest groups have become aware of the site. It has been and will remain a permanent local landmark.

Eagle Rock has enriched the postmine landscape for wildlife, archeology and postmine topography benefiting the surrounding community. It is a local landmark with ties to the community. It has been retained and made more prominent than it was prior to mining by the additions of an innovative bluff extension and reclamation plan.

Submitted by:

Robert Montgomery, Environmental Supervisor
Area C Office, Castle Rock Road
Colstrip, MT  59323

Date: May 17, 2001

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