The Roman Northwest coal occurrence is located on the east side of Mount Kostuik, approximately 3.7 kilometres northwest of the Roman Mountain coal deposit and approximately 22 kilometres south of Tumbler Ridge.
The coal measures at Roman Mountain occur in a tight upright syncline (Murray syncline) at the top of the mountain and extend for up to 7 kilometres along strike. The syncline has a 4-kilometre strike length, is cored with Lower Cretaceous Gates Formation conglomerate and coal seams, and features steep reverse faults with associated folds and tectonically thickened coal. The cumulative thickness of Gates Formation seams is approximately 18 metres. Looking down strike, the mountain has a prominent core of Gates Formation D-conglomerate sloping outward across the Gates coal sequence to recessive gullies of Lower Cretaceous Moosebar Formation (Fort St. John Group) marine shale and then outward across the Gething Formation to shoulders of resistant Lower Cretaceous Cadomin Formation (Bullhead Group) conglomerate at the base of the Gething. The Cadomin Formation then forms the core of the Waterfall anticline on the northeast, which hosts the Trend mine (MINFILE 093I 030). The coal sequence is similar to that at Trend with Gates (D, E, F, G, J seams) and Gething (Bird and GT seams) of 18.3 metres and 7.5 metres cumulative thickness, respectively. Complexities including thrust faults and drag folding have been identified on the southwest limb of the syncline. Coal seams have been identified over a 3-kilometre strike length.
The Roman Northwest coal follows the close-folded Murray syncline and Waterfall anticline fold pair.
The Gates Formation (Fort St. John Group) is the major coal-bearing unit of the area and consists of siltstone, shale, sandstone, conglomerate and several cycles of coal deposition. It is generally subdivided into four subunits, termed the Upper Gates member, the Babcock member, the Middle Gates member and the Quintette member. The Quintette member, approximately 80 to 90 metres thick, consists primarily of massive, fine-grained siltstones and sandstones. The Middle Gates member, approximately 90 to 100 metres thick, consists of a series of fining-upward sequences that culminate in coal development, and hosts all of the economic coal seams of the Gates Formation. The Babcock member is a channel deposit sequence of massive sandstones, conglomeratic sandstones and chert pebble/granule conglomerates, averaging 20 to 30 metres thick. The Upper Gates member is a 30 to 40 metres series of shales and sandy shales with several thin, discontinuous coal seams. A very thin bed of ferruginous chert pebbles marks the top of the unit. Overall thickness of the Gates Formation is 270 to 300 metres.
The Gething Formation (Bullhead Group) consists of alternating units of fine- to coarse-grained sandstone, carbonaceous shale, coal, siltstone and conglomerate. Three to four significant coal seams occur in upper part of this formation, and form part of the Trend mine reserves. Historically, the Gething Formation coals have not been mined in this area. The upper contact is a thin bed of pebble conglomerate overlain by distinctive glauconitic, marine sandstones that form the base of the overlying Moosebar Formation (Fort St. John Group). Its thickness ranges from 120 to 200 metres.
In 2011 to 2012, Anglo American plc (Peace River Coal Inc.) completed an eight-hole large diameter core drilling program. The 6-inch large diameter core was drilled as a bulk sample for coal quality data and drop shatter tests. In addition, a diamond drilling program, totalling 5277 metres was conducted on the southwest limb of the syncline for structural data. The northeast limb was explored in 2008. The Trend mine expansion property lies 3 kilometres northwest of Roman Mountain and is a continuation of the close-folded Murray syncline. The syncline has a subsidiary chevron fold and plunges to the northwest through Mount Kostuik. Cretaceous Hulcross Formation marine shales (Fort St. John Group) form a weakly recessive core of the syncline at the top of the Gates coal sequence. As at Roman Mountain, the sequence moves outward from the syncline core through resistant D-conglomerate cliffs to Moosebar Formation shale gullies and then Cadomin Formation ridges. A thrust fault and drag fold add complexity to the lower seams on the northeast limb of the syncline. About 27.5 line-kilometres of geophysical survey were also completed. The experimental geophysical program began testing subsurface mapping capabilities of three geophysical techniques using seismic waves, ground penetrating radar and resistivity.
In 2013, Anglo American plc completed 2121 metres of percussion drilling, 1535 metres of core drilling and trenching. Winter drilling and trenching programs were completed from January through early April 2014.
In the early winter of 2015, Peace River Coal Inc conducted an exploration program to define coal seams of the Gates Formation in the centre of the Second syncline. The drilling program consisted of four rotary percussion boreholes totalling 1531 metres.
