| The project is considered by Bowen Energy Ltd to contain extensive areas with the potential to host underground coking coal. With just about all of the potential coking coal areas in the Bowen Basin covered with MLs, MDLs, and EPCs, the remaining target areas for coking coal within the Bowen Basin lies at depths of +300m. These resources will contain gas and may be subject to geotechnical challenges such as thrust fault zones and residual stresses.
Exploration within EPC 1045 is directed towards coal reserves that fall within the prime coking coal range of 1.0 to 1.2% coal reflectance zone and 300 to 800metres depth range in the Rangal Coal Measures. The projected position of the "1.0% reflectance line" is presented in Figure 1.
Previous exploration in the area of EPC 1045 comprises petroleum exploration drilling, seismic exploration for both petroleum and coal bed methane (CBM) and some wide spaced early coal drilling.
The geological setting of the region is well understood with The Rangal Coal Measures overlain by the outcropping Rewan Formation and which in turn overlie the Burngrove Formation. The Rangal Coal Measures are the formation of interest in the area containing the main coal seams worked in the Blackwater region ( including the Blackwater, South Blackwater and Cook Mines) for high quality medium to low ash coals suitable for prime coking coal, high quality PCI coal, anthracite and semi-anthracite, and high energy thermal coals. The project also lies immediately south of the RCI Rocklands coking coal project EPC 890. (Figure 1)
The general sequence of coal seams in the Rangal Coal Measures persists southwards with up to 5 coal seams generally including 2 major seams. Equivalents of the Blackwater named coal seam sequence (in descending order) of Aries, Castor, Pollux (Argo) Orion and Pisces can be identified either individually or as thicker coalesced coal beds from regional drilling. The base of the Rangal Measures is generally clearly marked by the occurrence of the regionally persistent Yarrabee Tuff. Coal seams in the Burngrove Formation below the Yarrabee Tuff are generally high ash, tuffaceous and not considered commercial.
In the area of EPC 1045, the coal seams dip gently to the east into the Mimosa Syncline from the Comet Ridge. Structural complexity generally decreases southwards from the Blackwater - Bluff area away from regions of structural complexity around the major regional faults eastwards towards the Gogango folded zone.
The Comet Ridge which extends south towards Rolleston and Injune has acted as a broad extensional zone with fewer large regional structures and faulted areas influencing the coal measures. The rationale for exploring in these areas is to define larger areas of less structural disturbance more suitable for underground coal mining.
Regional seismic surveys include programs such as the Bauhinia Downs Survey and the Friendly Hills Survey and these depict the coal seams of the Rangal Coal Measures as strong persistent and continuous reflectors in the seismic profiles to the east of Rolleston. Depths of available coal in the target coal quality range (prime coking coal) range from 300 metres to 800 metres. As indicated by seismic surveys and petroleum and CBM drill logs.
The composite petroleum well logs of Sunlight 1 and Humboldt indicate coal seams logged in the Rangal Coal Measures. These are confirmed by density & gamma logs for the Humboldt well, and SP and Resistivity logs for the Sunlight well. The detail from these older exploration holes does not allow specific coal seam correlations. However they show the persistence of the main coal seams at thicknesses of more than 2.0 metres across parts of the project area, although some coal seam splitting and coalescing is to be expected. The geophysical down hole logs from the petroleum exploration wells also demonstrate a number of coal seams with thicknesses in the order of 2.5 to 5.0 metres which would form a suitable height for underground mining.
The strong amplitudes of the gamma and resistivity peaks on the geophysical logs associated with logged coal seams indicates low ash coal seams with clean clear boundaries with the overlying and underlying beds. The project covers the interpreted coal rank range of 0.95% to 1.2% at the shallowest depths available in the area as defined by available coal reflectance data. These coal rank data are contained in a series of reports prepared by J. Beeston of the GSQ. The primary target zone is the 1.0 to 1.2% coal reflectance zone in the Rangal Coal Measures which is representative of prime coking coal. Coal in this range typically contains a volatile matter content range of 26% to 29% depending on ash content.
Because the coal rank is also increasing to the east into the Mimosa Syncline, coal reflectance and coking quality will be increasing with depth.
Bowen Energy Ltd is well equipped to tackle the technical requirements of exploring the region for underground coal resources and in their assessment and evaluation.
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