GEOLOGY AND COAL SEAMS
EPC 890 is located on the western limits of the Mimosa Syncline
and the eastern flank of the Comet Ridge in the Permian Bowen Basin.
The economically important section of the stratigraphic sequence in this
area begins with the Upper Permian sequence divided into the Fair Hill
formation (labile sandstones, tuffaceous sandstone and some coal beds)
at the base, the Burngrove Formation (carbonaceous mudstone, siltstone,
sandstone and coal) and the Rangal Coal Measures at the top. The Rangal
Coal Measures contain the main coal seams of interest together with carbonaceous
mudstone, siltstones, feldspathic and lithic sandstones and tuff.
Lying above the Permian sequence is a well developed Triassic succession
of sandstones, mudstones, shale, conglomerate and red beds. This Triassic
succession is divided into three formations - the Rewan Formation (at
the base), Clematis Sandstone and the Molayembar Formation at the top.
This sedimentary sequence is overlain by younger rocks of Tertiary age
including basalts (which commonly cap local hills), laterites and alluvial
sediments.
From previous exploration drilling to the north on the western margin
of EPC 890, the following seam correlations (Staines, 1975) are projected
through the EPC. The Rangal Coal Measures seams present in descending
order are:
Aries Seam
Castor Seam
Pollux / Argo Seam
Pisces Seam
The Aries Seam has been shown to have a thickness
of 2.0-3.5m from previous drilling along the northern and western boundaries
of EPC 890 . The 2005 drilling has shown that the Aries I and Aries II
seams persist with a similar combined coal thickness into the south of
the EPC and with similar average thickness to that in the South Blackwater
Mine to the west. The thin split between the Aries I and Aries II seams
occurs in the middle northwest sector of the EPC but does not persist
throughout all of the area drilled.
The Castor Seam in the area drilled in 2005 has a thickness
of 1.0-1.3m.
The Pollux / Argo Seam has thicknesses ranging from 2.5m
in the north to as much as 5.0m outside the western boundary of the EPC
into South Blackwater, but thins to 2.0m in the 2005 drilled area at the
south of the EPC.
The Pisces Seam shows a persistent thickness of 2.0-2.5+m
through the western part of the coal measures following a north-south
trend, but the drilling in September 2005 by the company did not intersect
this seam - the deepest economic seam intersected being the Argo.
Analyses of the coal seams intersected in the recent drilling program
are not yet available. However, previous exploration work suggests that
the economically interesting coal within the EPC area is likely to be
of similar quality to coal presently mined at the nearby South Blackwater
and Cook Colliery mines.
Coal Resources and Recent Drilling
Meaningful estimation of in situ coal resources requires a large
number of data points such as reliable drill holes evenly spread throughout
the area of interest. Unfortunately this is not yet the case for the entire
EPC 890 as earlier drilling was mainly concentrated in the northern end
of the lease and the 2005 drilling has tested only the southwestern zone.
However, general observations can still be made based on the known data
points and indirect methods such as seismic survey results.
In the southwestern area of the EPC there is a large area where coal (at
economic seam thicknesses) occurs up to depths of 250 metres. Recent drilling
in this area has confirmed the presence and persistence of two thick coal
seams (Hayes, 2005). The drilling was carried out during August September
2005 and the eight holes program included open hole drilling (with down-hole
geophysical logging) and some coring.
The main economic coal seams intersected were the Aries and Argo, which
are shown to be persistent throughout the drilling area. The thickness
of the Aries seam intersected was quite consistent between 3.5-3.8 metres.
The shallowest depth at which the Aries seam was intersected was at 153
metres in Hole RK02. There is a split in the seam which disappears to
the east. The Argo seam that was intersected in the drill holes, occurs
some 40 metres below the Aries seam, and is shown to have a thickness
of 2.0 2.7 metre.
Measured Resources - A small resource estimate has been
made around cored and analysed holes Rk02/Rk07 & Rk 03/08 based on
the demonstrated geological and quality persistence of the main seams
in the defined area and nearby holes.
Indicated Resources - have been estimated from the cored
holes and extrapolated to adjacent geophysically logged holes to demonstrate
the uniform persistence of the main seams over the defined area up to
500m beyond geophysically logged holes closest to the cored holes.
Inferred Resources - have been extrapolated to a maximum
distance of 2 km beyond the cored and geophysically logged holes because
of the strongly demonstrated persistence of the main seams in the defined
area.
Proposed Exploration Program
The proposed exploration program over the first two years is
designed to initially test for the presence of the two main coal seams
in the less explored areas of the EPC - and in particular the south-western
section where the coal is likely to be at shallower depths (from 100 to
300 metres). The persistence of the coal seams, their thickness, structure,
quality and rank will be factors that will be determined in this program.
This work will involve the drilling of a number of holes from 150 to over
500 metres in length. Holes will be geophysically logged, and some cored
sections through the coal seams will also be made.
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