Summary:
Geology of the Properties
The geology of the properties is consistent with regional structural trends. In Maryland, the local Casselman synclinal fold is evident in the Casselman mine. Coal seams of economic importance on the properties typically range from 1 foot to 6 feet in thickness and are primarily low-volatile in rank. There are 11 coal seams on the properties that demonstrate reserve or resource potential including, in descending stratigraphic order: Sewickley, Redstone, Pittsburgh, Bakerstown, Upper Freeport, Lower Freeport, Upper Kittanning, Middle Kittanning, Lower Kittanning, Brookville, and Mercer.
Mineralization
Mineable coal seams within the properties are typically low-ash, low to high-sulfur, and high-thermal content bituminous coals. Regionally, the coals are typically low-volatile in rank, with rank increasing from west to east. The maximum seam thickness may reach over 6.0 feet where multiple coal benches occur in proximity to one another; however, the average mineable thickness of the seams in this evaluation generally ranges from 1 foot to 4 feet. Seams are generally continuous but may be locally absent. Secondary discontinuity due to erosional features is present in most areas, resulting in seam outcropping, or visible exposure of the seam at the surface. Other than oxidation of the coal exposed at the surface, erosion of the seams has no significant impact on the mineralized deposits. Mineable seams associated with the properties are generally outcrop-accessible. Coal seams are characterized by both single-bench and multiple-bench coal horizons with parting (non-coal) material varying by seam and area. Seam parting is common within the coal seams on the properties with intra-seam parting material increasing drastically in some areas. Roof strata are typically shale or sandy shale with zones of sandstone roof being common. Floor strata are typically sandstone, shale, sandy shale, fireclay, or in the case of the Upper Kittanning, limestone.
Limestone beds occur within the various stratigraphic groups of the region. Some of these limestone beds are extracted in conjunction with surface mining of the Sewickley coal in particular.
Casselman – Upper Freeport Seam Reserve
Casselman is an actively mined underground mine. The mine produces from the Upper Freeport seam. Formerly, Casselman North reserves were reported separately; however, those reserves are now being mined from the same mine portal as the active Casselman mine. Therefore, Casselman North reserves are now combined with those for the Casselman mine. Average seam thickness for the Casselman reserve is 3.3 feet.
Casselman North – Upper Freeport
Corsa has acquired several scattered leases totaling approximately 1,899 acres north of the current Casselman mine and Interstate Highway I68. At Casselman, Corsa drilled 12 exploration holes North of Interstate 68 in 2017 & 2018 to collect Upper Freeport seam data with the intent of future development. Eleven of the twelve exploration holes are located within the Proposed North Permit Expansion boundary. Seam thickness for nine of the twelve holes ranges from 2.50 to 3.95 feet with an average of 3.03 feet, and the average raw and washed coal quality for these nine holes is very consistent with seam quality data of the Casselman mine, south of the interstate. Three of the exploration holes have Upper Freeport seam thickness heights less than 2.5 feet. These three holes are located in the east and northeast portion of the Proposed North Permit extension. Additional drill hole exploration is needed here, in the North Expansion, to further define coal thickness trends.
Deposit Types
The coal reserves reported herein are bituminous coals. The primary coal-bearing formations on the properties are Carboniferous in age, being in the Pennsylvanian system, which includes the Monongahela, Conemaugh, Allegheny, and Pottsville groups. The average mineable seam thickness for coal horizons in these formations ranges from 1 foot to over 6 feet. The coal seams are generally continuous and non-complex but may vary in thickness and may also be locally absent. Seams retain normal stratigraphic sequence throughout the properties and no evidence has been observed that seams have been modified from pre-deformational thicknesses.