PERMFILE73169

• Permit No: C1981013A
• IBM Index Class Name: Permit File
• Doc Date: 7/3/2003
• Section_Exhibit Name: Section 2.05 Operation and Reclamation Plan
• Media Type: D
• Archive: Yes

• The coal mined at the Golden Eagle is from the Maxwell Seam
found in the middle of the Raton. The overlying strata
consists primarily of laminated and slickensided shales with
several coal beds of varying thickness. Sand channel
washouts are commonly found in the overlying shales and
occasionally cut into the coal seam. Localized faulting is
often associated with these sand channels. No regional
faulting is known to have occurred within the mine plan
area.
•
Area Topography: The Purgatoire River, tributary to the
Arkansas River, is the major surface feature in the area.
The head waters of the Purgatoire are located on the eastern
slope of the_Sa_ngre de Cristo Range a few miles west of the
permit area. The three major branches of the river, the
North Fork, Middle, and South Fork all converge within or
just below the permit area. The Purgatoire is a consequent
stream whose location is not controlled by lithologic nor
structural anisotropies.
The area contains two levels of rock benches that are strath
terraces with an alluvial veneer. These straths are located
approximately 90 and 170 feet above the river. They have
been eroded from shale and siltstone containing thin
interbeds of fine to very fine, silty sandstone. The
overlying alluvium has a maximum thickness of approximately
35 feet and is composed of predominantly silt and sand
containing pebbles and occasional clasts up to 20 inches in
diameter. Deposits of caliche are common.
Two levels of alluvial terraces lie adjacent to the river.
These terraces are located 5 to 10 feet and 40 to 50 feet
above the Purgatoire. They are composed of relatively
unweathered, gray to light tan alluvium overlain by medium
to dark brown sandy overbank deposits.
Rock Mechanics: Discussed in Section 2.05.6 (6)(b)(B) 1).
(e)(i)(C) Local Experience With Subsidence: Monitoring of
longwall mining at the Golden Eagle mine has documented
vertical displacement of up to six feet. The mining height
typically was 6-8 feet at a cover of 500 to 700 feet.
Reportedly, longwall mining at the Allan seam resulted in
maximum vertical displacement of three feet over 6 foot high
longwall panels and a maximum horizontal displacement of
less than one foot.
(e)(i)(D) & (E) Predicted Subsidence: Monitoring of the
Northwest #1 Longwall panel has determined that subsidence
will occur as a result of longwall mining. Mining at depths
of 500-700 from the surface has resulted in subsidence of
• 2.05-57
(Revised 05-18-94)