Exxaro Resources Limited
Consolidated Mineral Resources and Mineral Reserves report 2022


Grootegeluk is a large multi-seam, multi-product surface coal mining operation that has been operating since 1980. Grootegeluk has a long-term CSA with Eskom. The RoM is hauled to five tipping areas, which feeds six different beneficiation plants. The largest portion of the beneficiated product is power station coal, which is continuously dispatched to the Matimba and Medupi power stations via a conveyor belt system. Several sized metallurgical coal products, semi-soft coking coal and steam coal are railed to various customers and shipped internationally. A small portion of the total product is sold on site to smaller customers and dispatched by road.

Grootegeluk overview

Table 40: Grootegeluk overview

Topic Information
Location 25km west of the town of Lephalale in Limpopo, South Africa

Previous ownership

Material notes

1960s to 1980

Yskor - Iscor - Iscor mining - Kumba

Exploration drilling

1980 to present

Kumba - Kumba coal - Exxaro Resources

Mine commissioned in 1980. Mine in operation approximately 42 years. Continuous exploration drilling to increase Resource confidence as well as aid structural delineation and overburden classification.

Adjacent properties

Thabametsi to the west


Grootegeluk can be reached from Lephalale via the hard-topped Nelson Mandela Drive, which is linked to the R510 road connecting Lephalale to the town of Vaalwater to the south and the Stockpoort border post between South Africa and Botswana to the north. Power supply to the mine is obtained directly from Matimba power station via two 132kV lines that supply the mine's three 840MVA transformers. Raw water is delivered to the mine and to a water treatment plant on the farm Zeeland by the 700mm diameter Hans Strijdom pipeline. The pipeline originates at the Mokolo Dam. Potable water from the Zeeland water-treatment plant is in turn routed to the mine and local communities.


Grootegeluk is located in the Waterberg coalfield and the coal seams are from the Volksrust and Vryheid formations.

Main seams

The upper part of the coal deposit, the Volksrust Formation (approximately 60m thick) is classified as a thick interbedded seam deposit type, comprising intercalated mudstone or carbonaceous shale and bright coal layers. The Vryheid Formation (approximately 55m thick) forms the lower part of the coal deposit and comprises carbonaceous shale and sandstone with interbedded dull coal seams varying in thickness from 1.5m to 9m. It is therefore classified as a multiple seam deposit type.

Seam development

These coal seams are subdivided into 11 coal zones which are further divided into separate coal and non-coal samples for analysis. A total of 77 samples are analysed per full succession drill hole. The Volksrust Formation consists of 30 coal samples and 30 non-coal samples whereas the Vryheid Formation consists of 13 coal samples and four non-coal samples for the Vryheid Formation.

Depositional control

The Zoetfontein fault forms the boundary of the Waterberg coalfield in the north while the Eenzaamheid fault forms the boundary in the south. The Daarby fault, with a throw of some 350m, divides the coalfield into a deep north-eastern portion and a shallow south-western portion. The first fresh coal in the shallow south-western portion is on average 20m below surface. The lowermost coal seam (Zone 1) occurs at a depth of about 130m in the shallow portion of the coalfield but this may vary depending on the local structure. The predominantly horizontal coal-bearing formations have a very gentle dip to the south-east near Grootegeluk. Only a few dolerite dykes outcrop in the south-eastern portion of the Waterberg coalfield and no sills have been encountered in any exploration drill holes drilled in the mine right area to date.

Resources and Reserves

The Resource extent is restricted by the depositional controls discussed above. The Reserves are restricted within the Resource blocks. The reporting of LoM is limited to the lapse of the mining right although Coal Reserves exist well beyond this date. There is a small area of the Thabametsi mining right included in the Grootegeluk LoM (Figure 14) due to practical considerations. Both rights are owned by Exxaro.

Mining method

Grootegeluk comprises one open-pit mine, which includes three overburden benches, 10 RoM benches and four interburden benches. A series of parallel benches are advanced progressively across the deposit via a process of drilling, blasting, loading and hauling with truck-and-shovel fleets. RoM is transported to the Grootegeluk beneficiation complex via haul trucks and in-pit crushing and conveying systems.


Grootegeluk makes use of six processing plants to beneficiate coal. This includes four dense medium separation beneficiation plants and two crushing and screening plants.


Various sized metallurgical coal products at 15% ash and 11.25% ash, semi-soft coking coal at 10.3% ash, as well as steam coal at 12.5% ash are railed to various customers and shipped to international customers via an export harbour. A small portion of the total product is sold on site to smaller customers and dispatched by road.


Local and export markets

Mining right

Grootegeluk has an approved mining right that covers some 8 703.35ha.

Environmental approvals

All environmental appeals have been favourably addressed for the declared Reserves.

Projects/feasibility studies

The Grootegeluk Alternative Mining Solution (GGAMS) BFS project was aimed at reviewing various technology alternatives for the transportation of OVB material from Grootegeluk's mining pit to its In-Pit Discard Backfill system. To achieve this, the overburden was modelled in various material types with associated levels of confidence (Measured/Indicated/Inferred). The results indicated that the confidence levels of the OVB material types, OVB volumes and tonnages, top of coal and geological structures vary throughout the LoMP areas. For the areas of low confidence, proactive exploration drilling campaigns are required to ensure that increased levels of OVB confidence are available for accurate mine design and planning.

The GG AMS study concluded that the base case trucking solution was still the most economical mining solution as opposed to an OVB impact crush and convey system.

Figure 14: Grootegeluk mine

Figure 14: Grootegeluk mine

Figure 15: Grootegeluk cross-section

Grootegeluk cross-section

Resource estimation

Table 41: Resource estimation methodology and reporting

Process Information
Drilling, logging and sampling

In order to have sufficient material available from each sample for the required suite of analyses to relative densities of 2.20g/m3, large-diameter: 123mm diameter rotary core drill holes. The large diameter drill holes are drilled in between the existing 500m x 500m grid of small diameter drill holes. The reason for this placement of large diameter drill holes was that the analysis of samples from the large diameter drill holes could be used to supplement the analysis of existing small diameter drill holes where samples and density fractions were absent. Sampling of drill holes is only conducted after the stratigraphy has been correlated. The geologist in charge supervises all drill hole drilling and is responsible for logging and sampling.

Laboratory and accreditation

Bureau Veritas, SANAS T0469.

Laboratory dispatch and receiving process

Each sample submitted to the laboratory is accompanied by a unique sample number for validation and tracking, as well as a submission list that serves as a sample advice sheet with instructions for analysis.

Laboratory QAQC

As part of the QAQC, audits are performed internally and externally. Bureau Veritas is accredited for analytical work and participates in monthly local and international round robins.

Data datum

WGS84 - LO27

Drill hole database


Number of drill holes in MR

1 496

Number of drill holes used for Resource estimation

1 341

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 acQuire.

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: Zone 1 floor
The model extent is limited by the Daarby and Eenzaamheid faults

Model outputs

Roof, floor and thickness grids generated for structure

Raw and wash quality grids

Changes to modelling process


Thickness cut-off and extraction height considerations

Opencast ≤0.5m

Quality cut-offs (adb)

≥65% ash Volksrust Formation coal, ≥50% ash Vryheid Formation coal

Geological loss applied

Variable per bench, calculated each year considering geological model estimation error and physical geological loss.

Table 42: Resource classification criteria

Category Type of drill holes Drill hole spacing Structurally complex areas Drill holes/ha

Cored drill holes with applicable coal qualities

0m to 500m

(Matrix) Additional geophysically logged drill holes needed



Cored drill holes with applicable coal qualities

500m to 1 000m

(Matrix) Additional geophysically logged drill holes needed



Cored drill holes with applicable coal qualities

1 000m to 3 000m

(Matrix) Additional geophysically logged drill holes needed


Table 43: RPEEE considerations

Item Criteria Criteria met Comment
Geological data

Data has been validated and signed off by Competent Person


Geological structures, seam thickness ≤0.5m, ash content ≥65% ash Volksrust Formation coal and ≥50% Ash Vryheid Formation coal. Coal qualities reported on an adb.

Geological model

Geological model has been considered and signed off



Structural model

Structural model was considered and signed




Mining assumptions were considered and defined




Exxaro internal audits and external audit were conducted


Internal review on Resource processes and LoM in 2022.

Economic evaluation

Conducted an exploitation study with economic and mining assumptions, including geotechnical and geohydrological assumptions


Exploitation strategy over mining right.


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


All applicable approvals are 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 with no impediments is valid until 2041 and there is a reasonable expectation that the right will be renewed.


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


Existing infrastructure adequate and can be upgraded with new required infrastructure under construction.


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


Current CSAs for local and export markets.

Reserve estimation

Table 44: Reserve estimation

Topic Information
Software OCCS
Reserving process Production scenarios are defined by scrutinising different market demand scenarios for product sales, as well as evaluating estimated future installed production capacity. Ultimately, care is taken to select the most probable scenario to be scheduled as the LoMP.

Once the RoM and product schedule are completed, a process is followed whereby the OVB and interburden scheduling is altered, to obtain a "smoothed" year-on-year ex-pit profile, to prevent erratic mining equipment requirements.

The pit shell is designed from an economic and product quality perspective to ensure the longevity of the Grootegeluk operation.
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, Measured Resources are either not converted or the Measured Resources are converted but downgraded to Probable and the associated risk is clearly stated. Inferred Resources are not converted to Coal Reserves.
Inferred Resources inside LoM Some 73Mt of Inferred Resources are included in the LoM plan, representing 2.8% of the LoM plan, and are not considered material. The impact of the Inferred Resources is known with the majority thereof occurring at the tail end of the LoMP and addressed by an integrated exploration plan that is reviewed every year.
Modifying factors  
Average thickness cut-off ≤0.5m
Quality cut-offs ≥65% ash content (raw in situ)
Mining loss No loss applied as all mining boundaries are reached, and no pillars are left
Boundary pillar N/A
Dilution No dilution is planned
Contamination No contamination factor is applied
Mining recovery efficiency Varies per bench 0 to 0.75m depending on bench height
Planned average slope angles <61.7 degrees
Practical plant yield Considered in the reserving process as per wash table information per combination of blocks per planning increment and the empirically determined practical yield adjustment factor.
Strip ratio cut-off Energy strip ratio >7GJ/ex-pit tonne
Environmentally sensitive areas Areas underlying wetlands and other eco-sensitive areas are excluded from the Reserves, distance as per environmental requirements.
Legal The layout is within the mining right boundary and not closer than 15m.
Social There are no known socially sensitive areas in the pit layout (for example, graveyards and dwellings).
Geohydrological Areas identified are flagged and excluded or reclassified in the reserving process.

Table 45: Grootegeluk Coal Resources and Coal Reserves statement

Category 2022
Difference in
tonnes (Mt)
Reason for change
Measured 3 039 2 481 558   22   The decrease is the result of mining (~59Mt) and the removal of a portion of bench 7B due to high ash content (~4Mt), which was offset by new information (621Mt).
Indicated 967 1 421 (455) (32) The decrease is the result of the removal of bench 7B to waste (4Mt) and new information (451Mt).
Inferred 178 338 (160) (47) The decrease is due to new information (160Mt).
Total Coal Resources 4 184 4 240 (56) (1)
Proved 2 034 1 682 352   21   The overall increase due to mining (58Mt) and the removal of bench 7B (28Mt) was offset by reconciliation (1Mt) and the change in Resource base (437Mt).
Probable 550 898 (348) (39) The decrease is the result of the removal of bench 7B (11Mt) and new information (337Mt).
Total Coal Reserves 2 584 2 580 4   0  
Rounding of figures may cause computational discrepancies.
Tonnages quoted in metric tonnes and million tonnes (Mt). Coal Resources quoted as MTIS.

Exploration summary

Table 46 outlines the exploration for the reporting year. For detailed expenditure, please refer to Table 64.

Table 46: Exploration summary

Objective Progress in reporting year Plans for the next reporting year

Geological and geotechnical overburden material characterisation, delineation of structures and resource classification

Seventy six (76) percussion holes drilled for OVB material classification and to aide in the delineation of faults in structurally complex areas

Four (4) shallow rotary core drill holes drilled for geotechnical characterisation of the OVB.

Ten (10) deep rotary core drill holes drilled to obtain samples for quality analysis and to aide in Resource classification

Ten (10) rotary core drill holes for Resource estimation and classification. Two (2) rotary core drill holes for geometallurgical studies.

Three (3) deep rotary core drill holes for geotechnical characterisation.

Thirty (30) percussion drill holes for OVB classification and structural delineation.

Three (3) percussion drill holes for water monitoring.


Table 47: Grootegeluk risks

Risk Description Mitigation
Unweathered OVB availability

Material in the west is more weathered with less shale material available

Borrow pit in the north to be constructed to source non-weathered material for backfill construction (included in the updated LoMP).

Management of excessive rainwater in the pit

Risk of flooding pit floor if rainfall is above mean annual rainfall; impact on B11 mining

Sump strategy and diversion of water from plant (included in updated LoMP).

GDIP phase 3 timelines

The plant waste is stacked using two progressing vertical levels known as the upper system and the lower system. These systems are approximately 860m and 900m above sea level respectively (860m-level and 900m-level). The 860 plant waste system is reaching the turn and the mine is at risk of having only one waste system running

Prolong utilisation of 860 plant waste area.

Delayed arrival of additional truck capacity

Mining capacity shortage in H1 2023

Mining contractor appointed to start mining sumps, alleviating some of the constraints on the fleet.

Full product stockpiles

TFR offtake challenges

Reviewing options to address the shortcomings in the TFR offtake as well as considering alternatives to optimise the transport to our various customers.

Operational excellence

Strategic backfill is crucial to the effective execution of Grootegeluk. New information distinguishing between the various OVB material types contributed to the mine integrating backfill and mining activities into a consolidated plan that enables detailed material destination scheduling. The plan provisions for a sump strategy for effective in-pit water management, which addresses a historical operational challenge in the large open pit. In addition, the plan includes consolidating and redefining certain waste mining benches based on economical and practical considerations and improving mining activity sequencing to ensure the continuous supply of suitable material to all specified destinations. The conclusion of the plan is an exceptional achievement for Exxaro.

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