The stratigraphy of the Maramarua Coalfield is similar to that of other northern Waikato Coalfields, being dominated by thick, Cenozoic, Te Kuiti Group sediments which unconformably overlie Mesozoic basement rock of the Newcastle Group. The Waikato Coal Measures, and later Te Kuiti Group sediments, were deposited in a broad north to northnorthwest trending elongated trough which appears to have been controlled by structural trends within the underlying Newcastle Group basement rock.
The Waikato Coal Measures are present over the entire coalfield with a thickness of up to 134 m.
The Kupakupa main seam (KK) is located near the base of the coal measures, is the most widespread and thickest seam, and ranges in thickness ranging from less than 1 m to 15 m.
The Kupakupa seam has up to four lower seams (KL1, KL2, KL3, KL4) located 1 m to 3 m below the main KK seam. These lower seams are discontinuous and generally less than a metre thick.
The Kupakupa seam is overlain by carbonaceous shales, siltstones and claystones of the upper Te Kuiti Group.
The generalised structure of the coalfield dips at 15° north-northwest and flattens out towards the Miranda Fault due to fault drag effects on the hanging wall.
Two major faults dominate the deposit.
-The Foote Fault zone is interpreted to be a large displacement fault striking northnortheast that is downthrown to the southeast with an estimated throw of 150 m.
-The ........