Summary

Mine Type	Open Pit
Study Completed	Prefeasibility
Study in Progress	Feasibility
Stage	Permitting
Commodities	Coal (metallurgical) Coal (hard coking) Coal (semi-soft coking)
Mining Method	Truck & Shovel / Loader
Project Timeline	...
Mine Life	...
Snapshot	The Buller Coal Plateaux Project Area comprises the existing Stockton and Cypress mines, the existing consented Escarpment and Sullivan pits with new authorisations over Mt Frederick South. The coal found in these areas produces high-quality metallurgical coal for steelmaking. The Pre-Feasibility has confirmed the Project’s high-level economics. With the project listed in Schedule A of the Fast Track Approvals Act 2024, this update highlights the compelling development opportunity that exists at the Buller Plateaux adjacent to Stockton. The proposed coal production feed from Mount Frederick South and the Escarpment Extension developments are blended with the remaining planned life of mine (LOM) coal resources from Stockton through the mine’s existing coal handling and processing infrastructure facilities and coal logistics network. The delivery of coal from both developments to Stockton is via the proposed Upper Waimangaroa Haul Road (UWHR).

Deposit type

• Sedimentary

Summary:

The Buller Plateaux Continuation Project (BPCP) encompasses three main coal deposits—the existing operational Stockton Mine (including Cypress), and the extensions at Mount Frederick South (MFS), and Escarpment Extension (ESE).

Denniston Plateau
The project is located in the Buller coalfield, New Zealand.

The Denniston Plateau is a north west dipping plateau bounded to the west by the Papahaua Overfold/Kongahu Fault zone, and to the east by the Mt William Fault.

The defined resource is contained within the Eocene aged Brunner Coal Measures. The coal measures consist of a fluviatile sequence of fine to very coarse sandstones, siltstone, mudstone and coal seams. The deposit generally has a single extensive seam with some localised splitting of the seam. The coal thickness can be up to 14m but generally averages 4-5m vertical thickness.

The dip of the Denniston plateau reflects the dip of the coal bearing sediments with localised exposures of basement units at structural highs and within incised gullies.

Little to no Quaternary deposits or soils overlay the Brunner Coal Measures with overburden generally around 40-50m.

A strong trend in coal rank exists across the deposit with coal rank increasing from east to west.

Dimensions
The main coal seam varies in thickness from less than 1m thick up to 14m thickness locally.

Depth of cover varies from 0m at outcrop to over 150m at the eastern margin of the Mt William Fault.

The deposit roughly covers a 6.5km by 4.5km area. The model is bounded by the Escarpment Fault to the south, the Waimangaroa Gorge to the north, and the Mt William Fault to the east.

Deep Creek & Mt Frederick South
The Deep Creek or MFS Resource is located on a deeply incised and faulted south facing plateau that lies between the Stockton Plateau and the Denniston Plateau and within the Buller Coalfield.

Coal resources are restricted to the Middle to Late Eocene aged Brunner Coal Measures (BCM). This unconformibly overlies the Ordovician aged Greenland Group greywacke’s and argillites, which has been extensively intruded by Cretaceous granites and porphyry (Berlins Quartz Porphyry). Due to the stratigraphic nature of coal measures, the coal seams generally lie in a horizontal or sub-horizontal plane. The BCM are present as a series of structurally dispruted dip slopes that generally dip at 5° – 15° to the south. The coal measures are bounded by the Papahaua Overfold /Kongahu fault to the northeast, the Mt. William fault to the southwest and the Cedar Fault to the east. Kaiata Mudstone overlies the BCM over much of the Upper Waimangaroa sector.

The upper part of the Brunner Coal Measures is dominated by massive-bedded quartz sandstones, mostly coarse to very coarse grained. There are also minor thin siltstone and mudstone beds and rare, thin rider coal seams.

The Mangatini coal seams are the main coal seams of the Deep Creek Deposit. The seams have been given the abbreviation M. There are the three seam packages - M1 and M2, merge into the M seam, whereas the M3 and M4 do not. The M1 and M2 seams are the predominant seams over the deposit. The M2 seam overlies the M1 seam. The M3 is a rider seam to the M2. Seam splitting is common across the deposit and can lead to correlation complications. No distinct marker horizons are present between the seams. Correlations are based on detailed cross sections completed across the deposit using Vulcan Geology Core correlation module. The M1 seam is the spatially dominant seam at Deep Creek and can vary in thickness and quality. The M2 seam has a maximum thickness of 9-metres and averages about 4-metres but is more likely to be eroded and missing from the stratigraphic sequence.

The basal coal measures are usually about 30-metres thick and mostly comprise coarse grained quartz sandstones overlying pebble conglomerate.

Dimensions
The Deep Creek resource area covers approximately 915 ha.

Within this area all seams are exposed at outcrop along the northern margin of the MP. With the bulk of the in situ coal between 0 and 150m below the original ground surface.

Coal thickness varies considerably over the deposit. The M seam averages 4-6m with a maximum thickness of greater than 10m.

Mining Methods

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Comminution

Crushers and Mills

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Processing

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Commodity Production

Operational metrics

Metrics
Coal tonnes mined	....
Annual processing capacity	....
Stripping ratio	....
Waste tonnes, LOM	....

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Nov 17, 2025
.......................	.......................		Nov 17, 2025
.......................	.......................		Nov 17, 2025
.......................	.......................		Nov 17, 2025

Total Workforce	Year
......	2025