The South Ridge coal property is located between Roman Mountain to the east, the Terminator Ridge to the north and Kinuseo Creek to the south, about 26 kilometres south of Tumbler Ridge. The property is about 2.7 kilometres southeast and along strike from the Horizon-North Ridge property (093I 032).
The Lower Cretaceous 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 sub-units, 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, 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 thick 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 Lower Cretaceous Gething Formation (Bullhead Group) consists of alternating units of fine to coarse-grained sandstone, carbonaceous shale, coal, siltstone and conglomerate. 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.
The coal measures of the South Ridge property form part of the Peace River Coalfield. Regionally, 11 coal seams have been identified in the Gates Formation, and a further four coal seams have been identified in the Gething Formation.
The structure of the South Ridge project area is dominated by a regional scale, northwest-trending syncline. The Five Cabin syncline (historical name for the South Ridge property syncline) is a relatively symmetrical open fold with generally less steeply dipping limbs than the adjacent Roman Mountain syncline to the northeast. The Five Cabin syncline plunges gently at 5 degrees to the northwest with a trend of 315 degrees. The eastern limb dips at 35 to 55 degrees to the west and the western limb dips at 25 to 50 degrees to the east.
A number of thrust faults have been interpreted within the South Ridge area, which are evident both at surface and in sub-surface borehole geophysical data. Interpretations confirm the presence of two major thrust faults and a potential normal fault, located on the western limb of the syncline.
The coal seams of the South Ridge project area are medium volatile bituminous in rank within the Gates Formation. The coal sequences in the Gates Formation consist of a cyclic succession of carbonaceous sandstone, mudstone, siltstone, coal and some conglomerate. Coal seams of the Gates Formation are termed, from the base up, the No. 1 through No. 8 coal seams. However, only the No. 1, No. 6 and No. 7 coal seams shows economic viability within the project area, where thicknesses and qualities permit. The Gething Formation coal seams are medium to low volatile bituminous in rank. The coal seams are termed, from the base up, the D through A seams, with only the B coal seam showing economic thicknesses. Due to the limited lateral extent and depth below surface, notwithstanding only two boreholes have intersected these coals, the Gething Formation coal seams are not discussed in any detail in this description. Individual coal seams of both the Gates and Gething formations may comprise a number of coal sub-seams ranging from a few centimetres to a few metres in thickness, separated by intra-seam clastic partings, also varying in thickness. Coal sub-seams may also coalesce to form a single coal horizon.
In the South Ridge area, coal measures of the Gates Formation are ranked high to medium volatile bituminous coal. Variable ash, medium volatile coal seams of the Gates Formation on the eastern limb of the South Ridge syncline provide sharp comparison to the relatively low ash, high volatile coal seams on the western limb.
Coal measures of the lower Gates Formation primarily consist of the No. 1 coal seam, which is divided into the S1_1 and S1_2 sub-seams. Both coal seams occur sporadically within the project area and have an average thickness of 0.87 metre and 0.42 metre, respectively. The S1_1 and S1_2 subs-seams are separated by the No. 1 sub-seam parting (P1_1), which has an average thickness of 5.41 metres. Although the S1_1and S1_2 sub-seams have been logged and modelled, they are of no economic significance (Coal Assessment Report 892).
A coal seam of economic importance is situated in the upper Gates Formation and termed the No. 6 coal seam. The coal seam consists of several sub-seams ranging in thickness from a few centimetres up to more than 3.55 metres, separated by intra-seam clastic partings varying in thickness from a few centimetres to nearly 4.98 metres. The thickness and frequency of these partings tend to increase towards the limbs of the syncline and are generally thicker in the south. Coal sub-seams may also coalesce to form a single coal unit. In general, the No. 6 coal seam is typically bright to lustrous with occasional dull coal laminae in the poorer quality zones. The upper part of the No. 6 coal seam is of better quality than the lower part. The No. 6 coal seam is divided into a number of sub-seams. The S6_0 sub-seam represents the basal coal horizon of the No. 6 coal seam and has an average thickness of 0.39 metre. The S6_0 sub-seam comprises predominately of hard, dull to lustrous coal with bright laminae. The S6_0 and S6R1 sub-seams are separated by a clastic parting termed the P6_0 parting. The P6_0 parting is typically a thin (2.08 metres) carbonaceous mudstone horizon with gritty lenses. When present, the S6R1 sub-seam is poorer in quality when compared to the S6_0 sub-seam and has an average thickness of 0.33 metre. The thickest of the No. 6 coal seam horizons is the S6_1 sub-seam, which averages 2.23 metres. The S6_1 sub-seam is typically bright to lustrous coal with occasional dull coal laminae at the base. The S6_1 sub-seam is separated from the S6_2 sub-seam above by the P6_1 parting. Generally, the P6_1 parting is a horizon of interlaminated, carbonaceous to coaly mudstone with occasional grit bands and pebbles. The P6_1 parting has an average thickness of 0.42 metre and displays a complex gradational characteristic. The S6_2 sub-seam has an average thickness of 0.59 metre and is generally bright to dull lustrous coal. A composite of the No. 6 coal seam can be correlated with a high degree of confidence throughout the project area. The No. 6 and No. 7 coal seams are separated by a significantly clastic parting termed the P6_2 parting. The P6_2 parting has an average thickness of 24.24 metres and varies in thickness between the north of the project area, where it is thickest and the south (Coal Assessment Report 892).
The No. 7 coal seam is divided into seven sub-seams, with only the S7_1 / S7_2 and S7_3 / S7_4 sub-seams being of economic importance. The S7_1 sub-seam is predominantly dull, inferior coal and is typically 0.40 metre thick. The S7_1 sub-seam is well developed in the northeast and southwest of the project area, but shales-out completely in some areas. This coal horizon is separated by the S7_2 sub-seam by a mudstone carbonaceous, sometimes sandy parting. The parting is referred to as the P7_1 parting and is typically 1.97 metres thick, but varies significantly throughout the project area. The S7_2 sub-seam is generally well developed throughout the project area, with an average thickness of 1.77 metres. The S7_1 and S7_2 sub-seams exhibit evidence of coalescing in the southeastern portion of the project area. Further up the stratigraphic sequence, the S7_2 and S7_3 sub-seams are separated by the P7_2 parting. This parting comprises carbonaceous mudstone, sandstone and/or siltstone, with pebbles. The P7_2 parting has an average thickness of 3.93 metres. The S7_3 sub-seam represents a major economic coal seam of the upper Gates Formation. The coal seam comprises predominately brittle, lustrous to dull lustrous coal. The abundance of bright laminae increases towards the upper portion of the horizon. The coal horizon is generally homogenous, but other intra-seam partings may also be present towards the base. The coal seam is typically 1.64 metres thick and separated from the S7_4 sub-seam by the P7_3 parting. The P7_3 parting (0.57 metre) is typically carbonaceous mudstone and interlaminated with sandy material. An abundance of plant fragments can also be observed. The S7_4 sub-seam is typically the same quality coal when compared to the S7_3 sub-seam, but is poorly developed in the southern portion of the project area. Typically, coal of the S7_4 is 1.84 metres thick, lustrous to dull lustrous coal with abundant bright laminae (Coal Assessment Report 892).
A 2006 exploration campaign of geological mapping and drilling on the South Ridge property found evidence of viable Gates Formation coal seams. The upper Gates Formation coal seams appear to have the best potential for exploitation, due to their thickness and potential metallurgical coal properties. The No. 6 coal seam shows the most promising resource potential. The western limb of the South Ridge synclinal feature is enticing, not only because of its resource potential, but its relatively flat-lying topography could provide an ideal open-pit location, with a sizable strike length. Currently the borehole spacing of 200 to 300 metres on the western limb is sufficient for a reasonable structural resource estimate, but additional in-fill drilling is needed to reduce the borehole spacing further and supplement the existing coal quality data. Bulk sampling will be required to provide test samples to simulate blend washability characteristics and aid plant design (Coal Assessment Report 892).
The earliest known record of exploration dates back to 1972 when two boreholes were drilled by Denison Mines Limited. In this preliminary phase of exploration, coal samples were taken and analysed but the resulting data is currently unavailable (Coal Assessment Reports 600, 601). The final surveyed position of the drilled boreholes is not certain.
In 1981, Crows Nest Resources Limited, a wholly owned subsidiary of Shell Canada Resources Limited, drilled a 240-metre borehole on the western limb of the South Ridge property. The lower Gates Formation stratigraphy was cored and coal quality results from this program suggested a medium-high volatile bituminous ranked coal.
In 1985, Crows Nest Resources Limited drilled a helicopter-supported incline borehole on the eastern limb of the project area which cored the upper Gates Formation stratigraphy. The initial interpretation of these two boreholes differs slightly for the coal seam stratigraphy known to be more accurate today (Coal Assessment Report 718). The interpretation of the boreholes has since been reinterpreted. No final surveying of the borehole locations was conducted.
From 1985 to 2005, there was a hiatus in exploration campaigns on the property. During the period from 2005 to early 2006, renewed exploration interest in the property led to some 14 boreholes being drilled in the project area. This phase of drilling was to achieve a broad assessment of future coal resources available to Hillsborough Resources Limited. The drilling program focused on delineating the resource area and obtaining preliminary coal quality data. The 14 boreholes were drilled along both limbs of the main synclinal feature, testing the resource potential of both the Gates and Gething formations coal seams.
In 2006, Anglo Coal Canada Inc. (a subsidiary of Anglo American plc), conducted a major air-rotary drilling program (9900 metres) on its South Ridge coking coal property. The program tested a 4.5-kilometre strike length of coal-bearing sedimentary rocks of the Gates and Gething formations. Like Horizon-North Ridge (093I 032), the stratigraphy is folded into anticline-syncline pairs which have fold axes following a northwest trend. Results from the project have not been made public, but the continuity of seams and consistency of seam thicknesses observed on the Horizon-North Ridge property likely extend onto the South Ridge ground (Exploration and Mining in British Columbia 2006, page 54).
