Exxaro Resources Limited
Consolidated Mineral Resources and Mineral Reserves report 2022


Leeuwpan has two operational opencast pits and continually participates in optimisation initiatives. Overburden removal was below budget due to contractor termination and challenges associated with a new mining business partner's onboarding. This also impacted subsequent pit liberation, which negatively influenced RoM and overall production.

Leeuwpan overview

Table 24: Leeuwpan overview

Topic Information
Location 10km south-east of the town of Delmas in Mpumalanga, South Africa.

Previous ownership

Material notes

1988 to 2006

Iscor – Iscor mining – Kumba

Exploration began in 1990, the first box cut was commissioned in 1992 and rights were ceded to Exxaro in 2006.

2006 to present


Infill exploration drilling; the mine has been in operation for approximately 32 years – OL has been operational since 2013, OI since 2018 and the western OI extension since 2020.

Adjacent properties

Stuart Colliery, Delta Mining Company and HCI Khusela Coal coal mines own property near Leeuwpan. Thaba Chueu Mine (silica mine) is adjacent to Leeuwpan.


Leeuwpan lies alongside the R50 provincial road and is serviced by a railway line that includes a rapid load-out station inside Leeuwpan's rail loop. Eskom supplies electricity to the mine directly by means of a substation at Witklip, which is linked to a nearby Eskom power line. Potable water is supplied from drill holes and pumped to different storage facilities, due to the presence of Escherichia coli (E. coli) bacteria this is used as grey water and purified water is purchased for drinking water. Process water is supplied from a closed system, which includes the plant, slimes dams and pit dams. Water replenishment for processing comes from the pits.


Leeuwpan mine is in the Delmas coalfield, on the western border of the Witbank coalfield. The geology within the Delmas coalfield is similar to that of the Witbank coalfield.

Like the Witbank coalfield, the Delmas coalfield has up to five coal seams in the middle Ecca group sediments of the Karoo supergroup. The Karoo sequence in the area is represented by the Dwyka formation and the middle Ecca with little or no lower Ecca development. The middle Ecca sequence of coal horizons, interbedded with sediments, is highly truncated due to erosion with minor areas where the full sequence is developed. The basement is generally the Malmani dolomites from the Transvaal supergroup.

Main seams

We identified two coal seams at Leeuwpan: top coal seam and bottom coal seam. The bottom coal seam correlates with the S2 of the Witbank and Highveld coalfields and the top coal seam correlates with S4 and S5. The bottom coal seam qualities are generally higher than the top coal seam qualities.

Seam development

The coal seams at Leeuwpan are primarily interbedded with sandstone, shale and carbonaceous shale.

Depositional control

The coal was deposited on glacial sediments of Dwyka tillite, which in turn was deposited on dolomite of the Transvaal supergroup. A significant amount of magma intruded as concordant sills of dolerite in the Karoo strata in the Delmas area. Thin dolerite dyke structures that transgress the stratigraphy are associated with the dolerite intrusion. Factors controlling geological and quality continuity are mainly surface weathering, significant variation in seam thickness due to an undulating tillite floor, faulting associated with dolerite activity and dolomitic basement, and devolatilisation and weathering due to dolerite intrusions (sills and dykes).

Resources and Reserves

Coal Resources and Coal Reserves occur in opencast pits OI, OL and UB.

Mining method

Leeuwpan is an opencast operation with Reserves in various pits mined simultaneously. Current mining operations are on the OL and OI Reserves. The mine uses a conventional truck-and-shovel mining method.


Leeuwpan has two dense medium separation plants that beneficiate coal primarily for the thermal export market and two crushing plants, crush-and-stack and bypass plants that handle selectively mined thermal coal either for the local market or the export market depending on the quality. The second dense medium separation plant, commissioned in 2016, is operated by an independent contractor whereas the original plant is operated by Exxaro.


The dry crushing and screening plants are capable of producing either a 4 200kCal, 4 800kCal or 5 300kCal product depending on the inherent coal qualities. The beneficiation plants are used to produce a 5 300kCal product.


Leeuwpan supplies domestic and export markets.

Mining right

Leeuwpan has an approved mining right that covers 4 269ha. Execution is pending following a section 102 to consolidate the two mining rights being granted.

Environmental approvals

Environmental authorisations are in place for the declared Reserves.

Projects/feasibility studies


Figure 10: Leeuwpan mine

Figure 10: Leeuwpan mine

Figure 11: Leeuwpan cross-section through pit OI

Figure 11: Leeuwpan cross-section through pit OI

Resource estimation

Table 25: Resource estimation methodology and reporting

Process Information
Drilling, logging and sampling

Vertical surface drill holes are drilled and subsequently logged on site. Lithological codes are used when capturing the lithology. Photographs of the core are taken after marking the core. Samples are split on the lithological contact, if needed, using a chisel and hammer to ensure a clean break. Each sample is put in an individual bag with all material represented in that interval, ensuring no contamination occurs between materials to be sampled. Two sample tags are marked using a permanent marker. One sample tag is placed inside the bag and the second on the outside of the bag then sealed with a cable tie.

Laboratory and accreditation


Laboratory dispatch and receiving process

All samples collected and bagged are registered in a sample sheet, which is also used as a dispatch sheet. The dispatch sheet is signed by the receiving laboratory personnel after ensuring that the number and sample ID on the dispatch sheet matches that of the actual samples to be analysed. Once the laboratory receives and signs the dispatch sheet, it is responsible for safekeeping and storing that batch of samples.

Laboratory QAQC

SGS is accredited for analytical work and participates in monthly local and international round robins.

Data datum

Cape datum – LO29

Drill hole database


Number of drill holes in mining right

4 128

Number of drill holes used for Resource estimation


Number of drill holes used for classification


Data compositing and weighting

Data compositing is conducted per seam using a weighted value from individual samples that make up the seam, along with the relative density and length of each individual sample. This is conducted in GEOVIA MinexTM.

Data validation

Conducted using queries in acQuire, MinexTM and Excel.

Geological modelling software


Estimation technique

Growth algorithm

Previous model date


Last model update


Grid mesh size

20m x 20m

Scan distance

1 000m

Data boundary


Model build limits

Upper: limit of weathering and topography/collar

Lower: basement/Dwyka

Model outputs

Roof, floor and thickness grids generated for seam structure

Raw and wash quality grids

Changes to modelling process


Thickness cut-off and extraction height considerations

2021 model ≤0.5m (S5 ≤1m)

Quality cut-offs (adb)

Ash ≥50%, a non-material amount of coal ≥50% ash may be included to ensure optimised extraction.

Geological loss applied

5% to 100% based on geological loss domains (5% standard geological loss is applied but may vary based on the consideration of structural complexity (dolerite sill breakthrough – 50% loss within determined spatial extent and fault displacement zone – 100%) and seam floor adulation (10% loss).

Table 26: Resource classification criteria

Category Type of drill holes Drill hole spacing Structurally complex areas Drill holes/ha
Measured Cored drill holes with applicable coal qualities 0m to 100m May be more conservative after consideration of RODA 1.04
Indicated Cored drill holes with applicable coal qualities 100m to 200m May be more conservative after consideration of RODA N/A
Inferred Cored drill holes with applicable coal qualities 200m to 1 000m May be more conservative after consideration of RODA 0.18

Table 27: RPEEE considerations

Item Criteria Criteria met Comment
Geological data

Data has been validated and signed off by Competent Person


Seam depth, seam thickness ≤0.5m all seams except S5 thickness ≤1m, ≥50% ash content but a non-material amount of coal with ≥50% ash may be included to ensure optimised extraction, coal qualities are reported on an adb.

Geological model

The Geological model was considered and signed off



Structural model

Structural model was considered and signed off




Mining assumptions were considered and defined




Exxaro internal audits and external audit conducted


External audit by EY in 2021.

Economic evaluation

Exploitation study with economic and mining assumptions, including geotechnical and geohydrological assumptions


LoM exploitation study (2022).


Reasonable demonstration that environmental approvals can be obtained within the context of local, regional and national governmental legislation


Current required approvals in place.


Formal tenure must be demonstrated with reasonable demonstration that a mining right approval can be obtained within the context of local, regional and national governmental legislation


Mining right valid to 2039 with no impediments noted.


Assumptions used should be reasonable and within known/assumed tolerances or have examples of precedence


Current infrastructure.


A potential market for the product with a reasonable assumption that this market is sustainable


Current market.

Reserve estimation

Table 28: Reserve estimation

Topic Information


Reserving process

Reserve scheduling is determined using a mine scheduling application (Scheduler) from OCCS, which is the same software used to develop the LoMP schedule. The geological three-dimensional (3D) model used for the Resource statement is referred to as the Reserve geological 3D model.

The geological model is supplied to mining, projects and technology in the form of MinexTM grids. The grids are then imported into a reserving application (Reserver) from the same OCCS software. This application validates the geological information received by checking the integrity of the geological structure and that quality and wash table values are consistent, and to convert the geological 3D model into mineable block sizes.

Careful product selection and balancing of remaining Reserves is required at Leeuwpan to ensure maximum value for Exxaro.

Conversion classification

Indicated Resources are generally converted to Probable Reserves and Measured Resources to Proved Reserves, after consideration of all applicable modifying factors. If one or more of the modifying factors have not been fulfilled, a Measured Resource is either not converted or the Measured Resource is converted but downgraded to a Probable Reserve and the associated risk is clearly stated. This is the case for UB, where it is classified as a Probable Reserve because of additional modifying factors such as low volatiles and the limited market for this particular quality of coal. Inferred Resources are not converted to Coal Reserves.

Inferred Resources inside LoM

No Inferred Resources inside LoM.

Modifying factors  
Average thickness cut-off

0.5m all seams except S5, which is 1.0m.

Quality cut-offs


Mining loss

S5 0.31m, S4U 0.12m, S4L 0.12m, S2U 0.5m, S2L 0.12m, UB S2 0.26m.

Boundary pillar

100m boundary pillar along the new R50 road at OI West pit.


S5 0.05m, S4U 0.11m, S4L 0.12m, S2U 0m, S2L 0.11m, UB S2 0.25m.


Included in rest of modifying factors.

Mining recovery efficiency

Included in rest of modifying factors.

Planned average slope angles

45 degrees. For highwall stability, soft material is mined at least one strip ahead of hard material and coal mining activities.

Practical plant yield

90% dense media separation and 90% Fraser Alexander dense medium separation with slimes loss on dense media separation of 9% and 15% on Fraser Alexander dense media separation.

Strip ratio cut-off

Strip ratio is determined using the energy strip ratio assessment and is considered in the reserving process using the economic model to get mining boundaries.

Environmentally sensitive areas

Environmentally sensitive areas applications made, and approval acquired before mining.


Applicable mining right considered, and all the reserved areas are within the mining rights boundary.


Applicable communities considered. Socially sensitive areas in the mining right (such as graveyards) are excluded from Reserves in the reserving process.


Applicable surface and groundwater models are considered. The pit floor was taken into consideration to minimise water handling in the pit face.

Table 29: Leeuwpan Coal Resources and Coal Reserves statement

Category 2022
in tonnes
Reason for change
Measured 65.8 77.9 (12.1) (16.0) The decrease is the result of mining (4.3Mt), model update (~1.5Mt), disposals (~3.4Mt), mining losses (~0.7Mt) and reconciliation (~2.2Mt).
Indicated 0.0 0.0
Inferred 3.6 3.6
Total Coal Resources 69.4 81.5 (12.1) (15.0)
Proved 36.1 40.2 (4.2) (10) The decrease is the result of mining (4.1Mt), mining layout changes (0.1Mt) and reconciliation (0.01Mt).
Probable 3.3 3.2 0.1 2 An increase of 0.1Mt is due to mining model refinement resulting in better plant simulation and less rejection of coal.
Total Coal Reserves 39.4 43.4 (4.1) (9)
Rounding of figures may cause computational discrepancies.
Tonnages quoted in metric tonnes and million tonnes (Mt). Coal Resources quoted as MTIS.

Exploration summary

Table 30 outlines exploration for the reporting year. For detailed expenditure, refer to Table 64.

Table 30: Leeuwpan exploration summary

  Objectives Progress in reporting year Plans for next reporting year
  Increase the Resource confidence levels in the UB pit Six (6) drill holes were drilled in the UB pit, increasing the Resource confidence level and de-risking the new box-cut area. Five (5) drill holes planned in OI East to increase Resource confidence. Six (6) drill holes planned in UB to increase Resource confidence and structure delineation.
  Delineate the sandstone washout encountered in the OL extension pit One (1) drill hole was drilled in OL extension to delineate a sandstone washout zone.
  Gain higher confidence in the OIOL bridge area Four (4) drill holes were drilled, delineating the geological structure and increasing confidence in the quality of coal in the area.


Table 31: Leeuwpan risks

  Risk Description Mitigation
  Dolerite sill impact slope stability Reserve blocks UB and OI have a dolerite sill overlying the coal strata and the sill orientation affects slope stability. Apply RODA to identify the areas of high geological risk. The bench design is modified based on dolerite dipping towards the seam.
  Dolerite sill impact coal devolatilisation The proximity of the dolerite sill may devolatilise or burn the coal seam. Higher geological losses are applied in the geological model based on proximity of the sill to the seams.
  Major/minor faults Major faults with displacements greater than the seam widths occur between OL and OI. This is also associated with sill transgression. Minor faults cause slight seam displacements which affect coal and quality continuity. Inclusion in the RODA plan and higher geological losses applied to major fault zones.
  Floor undulations Undulating floor conditions cause challenging and complicated mining environment (i.e. reduced production tempos and contamination). Floor gradient is included in the RODA. Use of floor contours to plan ramp gradients in each Reserve area.
  Coal quality In-seam quality deviations are generally localised and are associated with minor channel washout. Continuously monitor quality.
  Reserve losses In OI West, along the R50, the rock engineering design requires that a safe stand-off distance is established to prevent potential slope failure and infrastructure damage (Eskom power line and national road). Geotechnical design has been done to establish safe benching practice. Application in progress to allow mining within 100m of a power line and national road.

Operational excellence

Leeuwpan conducted five operational excellence initiatives in 2022 to improve its value add to the core value chain. These included aligning ROM production to the market to resource strategy and optimising contractor overburden removal, mining equipment and plant equipment effectiveness and cost management initiatives. These initiatives enabled Leeuwpan to mine remnants from pit OJ which were previously inaccessible due to proximity to existing infrastructure.

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