Summary:
The targeted coal seams for Shoal Creek are typically mid to high volatile bituminous coals, which can be sold as metallurgical coal due to high fluidity and coking properties. The coal seams of interest, Mary Lee and Blue Creek, are of Pennsylvanian Age and are part of the Mary Lee Coal Group of the Pottsville Formation within the Warrior Coal Basin of the Southern Appalachia Coal Producing Region. The thickness of the Mary Lee and Blue Creek seams is heavily dependent upon the location of the ancient fluvial system that scoured the topography with valleys. Areas where the ancient fluvial system scoured deep valleys allowed for thick peat accumulation and therefore thicker coal deposits for the Mary Lee and Blue Creek seams. The major ancient fluvial valley trends northwest/southeast across the Shoal Creek property. High angle normal faults are common across the property and often display horst and graben structures. The general strike of the coal seams is northwest/southeast, with a dip of one degree to the southwest.
The Mary Lee and Blue Creek seams are mined as one mining section at Shoal Creek utilizing underground mining methods. The depth of cover over the Mary Lee and Blue Creek seams at Shoal Creek ranges from approximately 800 feet in the eastern area of the property, to 1,700 feet in the west.
The coal deposit type of the Shoal Creek mine is considered to have a medium geologic complexity based on the following factors:
• The Mary Lee and Blue Creek seams are laterally continuous and can be correlated across the property with the use of geophysical logs, interburden thicknesses and seam thicknesses;
• The seams are gently dipping with numerous undulations due to the existence of the ancient fluvial system. This has added variability to the seam thickness of the Blue Creek seam;
• There are multiple high angle normal faults across the property, However, the faults do not prohibit the correlation of the Mary Lee and Blue Creek seams;
• The Mary Lee and Blue Creek seams are currently mined throughout the property across several counties;
• The local quality variations found throughout the property are not extreme enough to prevent a saleable product once the coal has been cleaned at the Preparation Plant.
Northern Alabama lies within the southern portion of the Appalachian coal region and contains three primary coal fields in the northern half of the state. These are the Warrior, Cahaba, and Coosa. The Shoal Creek property lies within the east-central portion of the Warrior Coal Field. The Warrior Coal Field is within the Pennsylvanian aged Pottsville Formation and is divided into two separate regions: The Plateau Coal Basin, and the Warrior Coal Basin which contains the Shoal Creek property.
The Warrior Coal Basin lies within the Cumberland Plateau section of the Appalachian Highlands and is bound on the eastern side by the Opossum Valley thrust fault. The Mary Lee Group outcrops along the northern and eastern edges of the Warrior Coal Basin. The southern portion of the basin is bound by the East Gulf Coastal Plain sediments. The Warrior Coal Basin dips one to two degrees to the southwest and the coalbeds plunge into the basin dipping as much as nine degrees.
The overlying strata of the Pottsville Formation are Cretaceous (145-66 million years ago) and Tertiary (66-2.6 million years ago) deposits of the Mississippi Embayment and Gulf Coastal Plain. The depositional environment associated with the Pottsville Formation of the Warrior Basin is interpreted as a barrier/back barrier setting with lithologic sequences that indicate marine nonmarine nearshore sedimentation. The lithology of the Pottsville Formation includes; interbedded sandstone, siltstone, claystone, shale, and bituminous coal. The thickness of the Pottsville Formation varies, with some local measurements exceeding 8,000 feet. The depositional sequences that are found within the Pottsville Formations usually follow this succession: a ravinement surface that is overlain by an interval of marine fossil assemblages, a thick gray mudstone that ranges in thickness from 30 to 300 feet, which then coarsens into sandstone and conglomerate. The sandstone is then succeeded by a heterogeneous coal zone that consists of mudstone, sandstone, conglomerate, underclay, and coal.
The Shoal Creek Mine is located within the Warrior Coal Basin. The coalbed mined is the Mary Lee and Blue Creek seams that are part of the Mary Lee Member Coal Group of the Pottsville Formation, which formed during the Pennsylvania age.
The Sequatchie Anticline and the Warrior Syncline are the two most prominent features influencing the structural attitude of the strata within the Shoal Creek property. The Coalburg Syncline is located in the region to the southeast of the Shoal Creek property. Faults tend to cluster within the two synclines, with one of the highest concentrations of faults located near the axis of the Warrior Syncline. The majority of the faults trend from the southeast to the northwest. The faults nearest to, and just west of the Warrior Syncline tend to be high angle (60 degrees) normal faults, as much as four miles in length, and with offsets ranging from 10 feet to over 240 feet.
Regional and local lineaments are present throughout the Shoal Creek property. The regional lineaments are orientated northeast to southwest and east to west. Local lineaments are generally perpendicular to the regional lineaments but can also be parallel. The coal cleat direction at Shoal Creek is usually N 60 E and joint direction is usually N 90 E, which follow the regional lineaments and fold axis orientations.
Three major coal groups are intersected in the drilling within the Shoal Creek property; Cobb, Pratt, and Mary Lee. Each coal group contains consistent coal marker beds, these are the Cobb, Pratt, American, and New Castle. The overburden down to the Cobb seam within the Cobb Group has an average thickness of approximately 475 feet. The interburden between the Cobb seam within the Cobb Group and the American seam of the Pratt Group has an average thickness of approximately 325 feet. The interburden between the American Seam of the Pratt Group and the New Castle Seam of the Mary Lee Group has an average thickness of approximately 450 feet. The Mary Lee Group is comprised of five coal seams, which in descending order are the New Castle, Mary Lee, Blue Creek, Jagger, and Ream. The interburden between the New Castle Seam of the Mary Lee Group and the Mary Lee Seam of the Mary Lee Group has an average thickness of approximately 40 feet but can range between 20 and 55 feet.
The interburden between the coal seams is primarily shales and sandstones, with thin fireclays underlying the coal seams in many areas. The sandstones are dark gray containing mica, clay and carbonaceous material. They are well cemented, of medium hardness and very fine grained. They range in thickness from less than 10 feet to approximately 40 feet.
The coal to be mined is the Mary Lee and Blue Creek seams which are in the Pottsville Formation. The Mary Lee and Blue Creek seams typically occur at depths ranging between 800 to 1,700 feet. The Mary Lee seam has a fairly uniform thickness ranging between 1 feet and 1.5 feet throughout the mine plan area. The Blue Creek seam ranges from 2.5 feet to 6.0 feet thick. This thickness is largely determined by interburden thickness below the Newcastle seam. A greater interburden thickness correlates with an increase in coal thickness.