Regional Geology
Dartbrook Mine is located in the northern part of the Hunter Coalfield and west of the Muswellbrook Anticline. The strata of the Permian Whittingham Coal Measures outcrop in the area and dip gently to the west. The underlying marine sediments of the Maitland Group outcrop approximately 3 km east of the site, on the eastern side of the Aberdeen Thrust. The Hunter Thrust, which represents the northern limit of the Sydney basin, is located further to the east (HLA-Envirosciences, 2000).
The Greta Coal Measures occur below the Maitland Group. These seams occur at depths in excess of 1,000 m at Dartbrook Mine (HLA-Envirosciences, 2000).
The Whittingham Coal Measures contain the coal bearing Jerrys Plains Subgroup and Vane Subgroup. Within the basin, these two subgroups are typically separated by the Archerfield Sandstone, which is a massive, well sorted sandstone unit. However, in the vicinity of Dartbrook Mine, there is no vertical separation between these subgroups, as the Bayswater Seam (the base of the Jerrys Plains Subgroup) has coalesced with the Wynn Seam (the top of the Vane Subgroup) (HLA-Envirosciences, 2000).
Four of the five main coal bearing formations within the Jerrys Plains Subgroup (namely the Malabar, Mt Ogilvie, Mt Thorley and Burnamwood Formations) are present at Dartbrook Mine. The coal seams within the Jerrys Plains subgroup generally exhibit a high degree of splitting, and major seams are generally re ........
