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Geology <br /> Geological information is found in Sections 2 . 04 . 5 and 2 . 04 . 6, <br /> pages 1 through 30 of the permit application. Below is a summary <br /> of the geology for the Southfield Mine area. <br /> The mine plan area is located along the east flank of the Wet <br /> Mountains adjacent to the axis of the north plunging Chandler <br /> Syncline. The syncline parallels the trend of the Wet Mountain <br /> Fault to the west . Strata on the northeast limb of the syncline <br /> dip gently to the west at approximately 5 degrees . The southwest <br /> limb of the syncline dips very steeply and in some cases strata on <br /> this limb are overturned. Dips in the southwest limb range from 45 <br /> degrees NW to 85 degrees overturned. The Wet Mountain Fault is <br /> comprised of pre-Cambrian granitic rocks uncomfortably overlying <br /> overturned sedimentary shales and sandstone units of the Cretaceous <br /> age. Three units are of significance in the area - the Pierre <br /> Shale, the Trinidad Sandstone and the Vermejo Formation (see Figure <br /> 3 ) . <br /> The Pierre Shale outcrops approximately 1 . 5 east of the mine area. <br /> The shale unit consists of 3 , 900 feet of olive-gray clay and silt <br /> layers that contain bentonite and marine fossils . It is a non- <br /> coal-bearing unit that exhibits very low hydraulic conductivity and <br /> thus is considered to be a relatively impermeable unit. At the top <br /> of the Pierre is a sequence of thin, inter-bedded sandstones and <br /> mudstones . <br /> The Trinidad Sandstone, directly above the Pierre Shale, outcrops <br /> about 1 . 0 miles east of the mine site and is composed of massive <br /> buff to yellow sandstones ranging from 40 to 90 feet in thickness . <br /> The Trinidad Sandstone is indicative of a prodeltaic depositional <br /> environment . <br /> The Vermejo Formation overlies the Trinidad Sandstone and is the <br /> coal-bearing unit of mining interest to the Southfield operation. <br /> The Vermejo Formation consists of a complex network of mudstones, <br /> siltstones, sandstones and eleven coal seams, all indicative of a <br /> vast fluvial delta and plain sequence. The coals developed in the <br /> backwater swamp areas of the river delta. The coal seams of <br /> economic importance in the area are Monarch, Red Arrow, Jack <br /> O ' Lantern, Vento, Manley and Rex Carbon. Total thickness for the <br /> Vermejo sequence is approximately 925 feet . <br /> The coal seams mined at the Southfield Mine are two of the six <br /> principal seams present in the Vermejo Formation - the Red Arrow <br /> Southfield Mine Permit Renewal 03 <br /> 17 <br />