GENERAL45390

• Permit No: C1981025
• IBM Index Class Name: General Documents
• Doc Date: 7/8/1983
• Doc Name: Proposed Decision and Findings of Compliance
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

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the Grand Hogback. In the area around the Sunlight Mine, there are three
minable coal seams; the "A-B" seam, the "C" seam, and the "D" seam. The
"A-B" seam and the "C'" seams have been previously mined, and the "C" and
"U" seams are currently being mined in the Sunlight Mine. Three
commercially minable coals of the Lower Bowie shale submember ("A", "B",
and "C" seams) are located in the area of the North Thompson Creek
Mines. The North Thompson Creek No. 1 Mine is currently mining the "A"
seam. The inactive No. 2 Mine was within the "B" seam. In the area of
the Coal Basin Mines, there are two minable seams, the "A" and "B"
seams. The "B" seam is being mined at the Coal Basin No. 1, 3, 4 and 5
Mines. The two seams are separated by U to 39 feet of interburden.
The Upper Bowie shale submember overlies the Middle sandstone submember.
This submember contains the Dutch Creek or Middle bed seam, which is
mined only at the Coal Basin No. 'L Mine.
The Middle and Upper sandstone submembers are deltaic beach front
sandstones. These sandstones are fine to medium-grained and poor to
moderately well sorted. The Upper sandstone member is slightly coarser
in texture.
The Paonia member is about 600 feet thick in the area of the mines, and
consists of interbedded sandstone, siTtstone, shale and coat beds. The
sandstones of this member are more lenticular and discontinuous, and
Their deposition represents a more terrestrial origin than the sandstones
of the Bowie member. There are six irregularly distributed coal seams
within the general area of the mines. These seams are, in ascending
order, the Placita, the Sunshine, the Anderson, the Lake Ridye, the
Thompson, and the Stony Ridge seams.
The North Thompson Creek No. 3 Mine is located in the Anderson seam.
This is the only active mine in a Paonia member coal. In addition to
these minable seams, the Paonia member contains several thin, lenticular
seams.
The Upper Barren member consists of between 'L,000 and 2,500 feet of
]enticular sandstones and gray shales. The lenticular sandstones
represent terrestrial stream channel deposits.
The Tertiary Age Wasatch formation - Ohio Creek conglomerate,
unconformably overlies the Mesaverde Group. This formation outcrops west
of the permit areas of the mines. The Wasatch consists of up to 5,800
feet of interbedded claystone, siltstone, sandstone, and conglomerate.
The Ohio Creek conglomerate consists of about 400 feet of sandstone and
conglomerate unconformably overlying the Mesaverde Group.
The sedimentary strata in the southern end of the Grand Hogback Monocline
have been injected by igneous dikes, sills, and a laccolith. The coal
beds in the Coal Basin Mines have been naturally coked as a result of
this igneous activity.
Unconsolidated Pleistocene gravel deposits occur as glacial remnants
capping some of the ridge tops.