2011-02-14_PERMIT FILE - C1980007A ‎(3)‎

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 2/14/2011
• Doc Name: SUBSIDENCE EVALUATION
• Section_Exhibit Name: Exhibit 60E Subsidence Evaluation for the South of Divide and Dry Fork Mining Areas
• Media Type: D
• Archive: Yes

Subsidence Evaluation for the
Exhibit 60E South of Divide and Dry Fork Mining Areas Page 25
c. Landslide area located above un -mined longwall panels 19, 20, and 21, on the east
side of Box Canyon in the W' /z of Section 14.
d. Landslide and rockfall area located above un -mined longwall panel 19 on the west
side of Box Canyon in the approximate center of Section 14.
e. Landslide located above un -mined longwall panel 18 on the east side of Box Canyon
in the NW' /+ of Sectionl4.
f. Extensive landslide area located south of the North Fork of the Gunnison River along
State Highway 133 in the S%2 of Sections 10, 11, and 12 and the N%2 of Section 15.
3. South of Divide mining area (Map 1):
a. An extensive landslide is located south of Minnesota Reservoir above the northern
part of projected E -seam longwall panel E9, in the N%2 of Section 32, Township 13
South, Range 90 West (Dunrud 1989). Overburden depth to the E -seam ranges from
500 to 550 feet. The average slope of the slide is roughly 20 percent. The landslide
contains more cracks and scarps in the upper part and more depressions and bulges in
the lower part than were present in the early 1960s (based on image data from July
1963 aerial photographs).
• Based on a stereographic review of July 2004 vertical aerial photographs,
• renewed activity occurred locally in western part of the landslide areas north
and south of Dry Fork during wet periods in the 1980s (1984 to 1987) and the
mid 1990s (1994 - 1996). The Dry Fork road was taken out one half -mile west
of the Minnesota Reservoir dam by this renewed movement in 1987 (Map 1).
b. Landslide located near the north shore of Minnesota Reservoir in the SW'/ of
Section 29. This slide is located on the border between the Apache Rocks and South
of Divide mining areas.
c. Landslide area located on the Dry Fork road in the approximate center of Section 31,
Township 13 South, Range 90 West. Two small landslides are located to the
southeast in the SE' /< of Section 31 and the SW' /< of Section 32.
d. Landslide located near the southwest corner of un -mined longwall panel E8 in the N%2
of Section 8 and the S' /2 of Section 5, Township 14 South, Range 90 West.
4. Dry Fork mining area (Map 1):
a. Landslides were identified on the Dry Fork mining area in the Final Environmental
Impact Statement prepared for the U.S. Department of Agriculture — Forest Service in
August 2005. The report identified three active landslide areas in the southeast corner
of the area These are located over the maximum eastern end of longwall panels E4
and E5. The erosional escarpment at the headwaters of Deep Creek is outside of the
area of influence mining. Two small landslides (slope failures) were identified by a
•
831 - 032.810 Wright Water Engineers, Inc.