The Burton and Lenton projects area lie within the Permo-Triassic Bowen Basin. Coal seams occur within the Rangal Coal Measures and underlying Fort Cooper Coal Measures which are Late Permian in age. The seams subcrop in the Mining Lease and generally dips at 15- 25 degrees North West at Lenton and mainly 10 to 20 degrees East at Burton with a section in the Ellensfield south pit up to 30 degrees. The main target seams are the Leichhardt and Vermont seams in the Rangal Coal Measures.

The seams split and coalesce significantly along the strike of the deposit. Cumulative seam thickness range between 5m and 10m for all the seams. The drill hole density (core and chip) allows for a high level of confidence in seam splitting, seam thickness, coal quality and location of subcrop lines. The area is structurally complex and the base of weathering is generally between 15m and 25m.

Burton
The Burton deposit is located 120 km westsouthwest of Mackay, Queensland. The ESPN (Ellensfield South (ES), Plumtree North (PN)) deposits occur immediately south of the Burton open cut pits which were mined by Peabody until early 2017. The Isaac Pit is located north of the Isaac River. Burton Mine produced coking and thermal coal for the export market.

The ESPN deposits are located on the eastern limb of the Nebo Synclinorium and target the Rangal Coal Measures (RCM). These coal measures are laterally continuous across the Bowen basin and were mined at the Burton open pits to the north of the ESPN deposits. Underlying the RCM are the Fort Cooper Coal Measures (FCCM) and these coal measures occur within the Permian Blackwater Group. The RCM are overlain by sediments of the Triassic Rewan Group, with Cenozoic cover unconformably overlying the coal sequence.

The RCM are comprised of fine to medium grained sandstone, siltstone, mudstone and coal. They range from 120 – 150 m thick and contain the Leichhardt and Vermont seams and these seams split significantly and coalesce along the strike of the deposit.

The FCCM comprise grey lithic sandstones, siltstones, mudstones and coal. The Girrah coal seam is a thick unit that is high in ash, interbedded carbonaceous mudstones and multiple tuffaceous claystone bands.

Ellensfield is in a structurally complex area with smale scale reverse faults having been identified during drilling and seen in geophysical logs. A fault zone, that contains several large normal faults and trends east-west is present in the northern portion of Ellensfield. Coal strata dips are between15-30° to the east-northeast. Large normal faults that have been interpreted have displacements in excess of 10 m.

Plumtree is also in a structurally complex area; however, the bedding strike is south-southwest with a shallower dip ranging between 10-17°. Several reverse faults have been interpreted with displacements in excess of 10 m.

The Isaac Pit contains numerous small-scale faults with a maximum displacement of 5 m to 7 m. Currently these faults have been interpreted to trend in East-West and almost vertical. Further drilling is required to delineate the extent and scale of these interpretations. Seams dip to the eastnortheast between 9-19°.

The Ellensfield and Plumtree North deposits are split by the Teviot Creek.

The Isaac Pit is bound by the Isaac creek to the south of the deposit with a small unnamed tributary located to the north of the deposit area.

14 coal seam “plies” are recognised in the Rangal Coal Measures in the ESPN deposits, in descending stratigraphic order the seams are named:
• BR
• LU
• LL
• V3U
• V3MR
• V3M4
• V3M3
• V3M2
• V3M1
• V3U
• V3L
• V1UL
• V1L
• GRH1 (Girrah Seam).

7 coal seam “plies” are recognised in the Rangal Coal Measures in the Isaac Pit deposit, in descending stratigraphic order the seams are named:
• BR
• BL
• BV3U
• BV3M
• BV3L
• BV2
• BV1.

The product make-up at Burton has been investigated to contain a split between coking and thermal coal from the RCM.

Lenton
The Lenton deposit is located 120 km westsouthwest of Mackay, Queensland. It is immediately west of Peabody’s Burton Mine which produced coking and thermal coal for the export market.

The Lenton project area is located on the western flank of the Nebo Synclinorium (whose eastern limb hosts the Burton Mine) and targets the Rangal Coal Measures (RCM). These coal measures were laterally continuous across the Bowen basin and were deposited during the Late Permian. Underlying the RCM are the Fort Cooper Coal Measures (FCCM). The RCM are overlain by sediments of the Triassic Rewan Group, with Cenozoic cover unconformably overlying the coal sequence. Tertiary filled paleochannels with basalt and present-day natural drainage channels with Quaternary alluvial sediments.

The Lenton deposit is bound by the Burton anticline to the east and the Burton Thrust Fault to the west. The Burton Thrust Fault is a regionally extensive east-side-up fault that trends north northwest with a vertical displacement of up to 600m. Multiple thrust and normal faults occur throughout the deposit and have been detected by both seismic and drilling data acquisition.
The major coal bearing unit in the Lenton deposit is the RCM, this includes:
• Burton Rider Seam
• Leichhardt Seam
• Vermont Seam.

The RCM are characterised by thick seams of bright coal, separated by tuffaceous and/or claystone partings and sandstone and siltstone interburden material. The underlying FCCM have also been intersected during drilling (Girrah Seam)

The FCCM are characterised by large of interbanded coal (50 cm thick) and stone bands. The economically targeted seams are within the RCM, which typically comprised an average of 50-60 m of alternating coal and interburden material, with a total coal accumulation between 7-14 m. Overall the seam dip is to the northnorthwest with seams cropping out to the south and east.

Thick coal seams, rare basalt flows, rare igneous intrusions, major thrust faulting and occasional normal faulting are characteristic of the Lenton area. Six coal seam “plies” are recognised in the Rangal Coal Measures at Lenton, in descending stratigraphic order the seams are named:
• BR
• BLU
• BLL
• BV2
• VU
• VL

The BR seam is separated from the remaining five seams by approximately 30 m of interburden material consisting mainly of sandstone and siltstone. The remaining five seams are deposited contiguously, and mining scenarios been undertaken for extraction as individual plies or as bulk mining horizons, depending on the target product. The average thickness of individual seams is approximately 1.5 m. The Yarrabee tuff separates the VU and VL seams. The product make-up at Lenton has been investigated to contain a split between coking and thermal coal from the RCM.

Open cut mining areas in Burton pits previously employed conventional truck-shovel methods. Prestripping of waste were performed by large hydraulic shovels and diesel excavators. Most of the remainder of the waste was removed by a fleet of smaller diesel excavators as post strip, depending on the number of seams and the burden thicknesses.

Waste dilution was estimated by assuming an average roof and floor dilution of 0.05m (each). Dilution density has been assumed at 2.2 t/m3. Dilution ash has been assumed at 85%.

Coal loss was estimated by assuming an average roof loss of 0.05m and average floor loss of 0.05m. Due to the past mining practices, dilution was favoured over loss.

No minimum mining width has been explicitly defined. Strips have been designed at a width of 25-50m in conventional down-dip mining areas. Standard coal blocks have been designed at a length of 100m.

Coal mining was performed by diesel excavators and rear-dump trucks. Coal from the Burton pits was hauled to the ROM stockpile near coal handling and preparation plant (CHPP) for crushing and washing. Coal mined from the project area were also sometimes stockpiled at intermediate locations between mining areas. Study proposed a contractor operated open pit and Auger operation.

A fleet of ancillary equipment will be used to support the primary mining equipment, including dozers, graders and water trucks. Rotary drills will be used to drill the waste material as required. One auger scheduled at a capacity of 750 t per day will be deployed for remaining coal in the highwalls targeting Vermont lower seams (VL1 and VL2) in two of the Lenton pits. Hydraulic excavators have been chosen for their flexibility as there will be movement of excavators in all the pits and ability to successfully excavate geologically complex deposits.

The mine schedule assumes both conventional strip mining and a terrace-style mining methodology utilising a combination of excavators and dozers.

Coal will be processed through the existing 2 X 400tph modules which has an annual name plate capacity of 5.5Mtpa. The existing CHPP will be restored to operating condition for the treatment of ROM coal. The coal will be mined in campaigns as it is exposed in the pit a proportion of the ROM coal will be placed directly into a raw coal dump hopper with the remainder temporarily stockpiled at the ROM before placement into the CHPP feed hopper. The main ROM coal stockpile is located within the CHPP operational area.

Raw coal is crushed and discharged onto a conveyor to feed the secondary crushing station. Coal is then reduced by the tertiary crusher prior to discharge onto the preparation plant feed conveyor. Dense medium cyclones are used to process the plus 1 millimetre (mm) size fraction due to their efficiency, flexibility and effective operation, with high proportions of near-gravity material. High efficiency spirals are used to process the relatively small tonnage of mate ........