PERMFILE52001

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 6/2/2006
• Section_Exhibit Name: Exhibit 60B Subsidence Evaluation for the South of Divide Mining Area
• Media Type: D
• Archive: No

Subsidence Evaluation For
Exhibit 608 South of Divide Mining Area Page 28
11.4.3 Ground Water Wells
The two monitored, ground water wells (23-H-1 and 23-H-2) in the South of Divide mining area
are located east of, and neaz the mouth of Deer Creek. They are located above, or within the
areas of mining influence of, the bamer pillar areas and haulageways of projected IongwaIl
panels E2 and E3. Overburden depth to the E Seam is approximately 375 to 400 feet. The major
source of the water in these is wells lrlcely from colluvium and alluvium in the Deer Creek
drainage.
These wells, and any other water wells within the area of mining influence should continue to be
monitored (or begin to be monitored) for as many years prior to mining as possible, in order to
determine baseline information that would yield seasonal variations.
11.5 Roads
With the exception of the presence of minor subsidence cracks on an access mad to Jumbo
Mountain, no subsidence features (cracks or bulges) were observed during the annual subsidence
observations. Large, extensive cracks were observed on Jumbo Mountain in landslide areas;
however, they were considered to be exclusively caused by the natural landslide process.
Based on past observations in the Apache Rocks and Box Canyon mining areas, no significant
effects from mine subsidence are expected on most of the access roads and drill road in the South
of Divide area. Also, no effects from landslide movements or rockfalls are expected, because the
• highest rockfall potential is mapped in the high category. Rockfalls were observed to occur only
in the very high rocltfall category areas in the Box Canyon mining area.
Although no cracks are expected in the soft, pliable alluvium, some cracks are expected to occur
on the harder and more highly compacted Dry Fork access road, paz[iculazly in dte area neaz the
confluence of Deer Creek and Dry Fork. As discussed previously, the range of maximum
vertical displacement, tilt, and horizontal strain is projected to be 8.4 to 112 feet, 1.3 to 6.4
percent, and 0.7 to 4.2 percent (respectively) in the Alorth Fork stream valley and road above the
solid coal boundaries at western limits of longwall panels E2 and E3.
11.6 Buildings

Subsidence effects on buildings have not been observed in the Apache Rocks and Box Canyon
mining areas. Baseline information on buildings, such as foundations, walls, chimneys, and
roofs, has already been obtained prior to any mining on the Dry Fork Cow Camp in July 2004
(Dunrud 20046). Apre-mining survey of the Cow Camp structures was performed by West Elk
Land Surveying in February 2006 and is included as Exhibit 73.
11.6.1 Lower Dry Fork Cow Camp
The cabin exterior is approximately 13 feet wide, 20 feet long, and 8.5 feet high (the wall
height). A lean-to 7 feet long and a porch 5.5 feet wide are located on the north and south ends
831-032.690 Wright Water Engineers, Inc.