Exxaro report selector 2019

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Exxaro Resources Limited
Consolidated Mineral Resources and Mineral Reserves Report

Currently viewing: Ancillary Resource and Reserve information by operation / Tumelo mine

Tumelo mine

Tumelo overview

Exxaro only provides an overview in projects and operations directly under Exxaro's management control. Tumelo shareholding is 51% Mmakau Mining and 49% ECC. However, we decided to include an overview of Tumelo since it formed part of the original Total Coal South Africa Complex.

Tumelo mine forms part of Exxaro Coal Central (ECC) and is in Mpumalanga, 15km north-west of the town of Hendrina and 5km south-east of Hendrina power station. The Hendrina-Middelburg tarred road passes 6km east of the property. An all-weather dirt road linking the town of Hendrina and the power station runs 500m to the west of the property, while the Wonderfontein-Broodsnyersplaas railway line lies 2km west with the closest siding being Pullenshope, 3.5km away.

Tumelo's mining right (10115 MR) covers 462.9ha on the farm Boschmanskop 154 IS. Following the purchase of Total Coal South Africa (TCSA) assets by Exxaro in August 2015, the current Tumelo shareholding is 51% Mmakau Mining and 49% ECC. The project is included in the ancillary section as Tumelo forms an integral part of the ECC complex.

Surface infrastructure still in use includes: mine buildings (offices, workshops and change houses), box-cuts to access the coal seam, conveyor belt systems and a RoM stockpile facility. After operating for six years, Tumelo ceased production in January 2014 after its mining contract expired, and it was placed on care and maintenance.

Since then, a series of technical and economic evaluations were conducted by TCSA and Mmakau Mining, reviewing the potential of the remaining mineable Reserves, mining method and production rate. Mmakau Mining recommissioned the operation in 2019 with first coal mined in April, this S2 ROM is trucked to FZON where the coal is then crushed and screened for a 5 300kcal/kg export market.

Tumelo exploits seam 2 (S2) on the edge of the Springs-Witbank coalfield and RoM was trucked using existing roadways to Forzando North (FZON) where it was beneficiated for a 5 800kcal/kg export product.

Tumelo history

Exploration activities started in the early 1990s with a mining right submitted in 2006 and first coal production in 2009. To date, there are 132 boreholes (103 with coal wash data) in Tumelo's mining right area. The 2017 geological model update incorporated all existing boreholes with wash quality information. In general, Tumelo has a borehole distribution of 0.22bh/ha.

Figure 28: Tumelo locality map

Table 72: Tumelo project history

Date range Company Material notes
1990 Senekal Mine The first company to conduct exploration programme, drilling 26 boreholes
1991 Hanover Mining Further exploration work, 34 boreholes drilled
2002 Total Exploration South Africa (TESA) TESA acquired the project with 18 boreholes drilled during its tenure. A feasibility study in 2002 confirmed the presence of economic Coal Reserves. The Boschmanskop project would later become known as Tumelo
2004 - 2013 Total Coal South Africa (TCSA) Further exploration work undertaken by TCSA. Mining right applied for in 2006 in the name of Tumelo Coal Mine. First coal recorded in 2009, exploiting S2 via bord-and-pillar method. Mining outsourced to SBS Mining Proprietary Limited, a mining contractor. Initially RoM coal was custom washed for an export product at the Shanduka (Glencore)-owned Koornfontein Colliery washing plant but would later be trucked to TCSA's FZON and washed for a 5 800kcal/kg export product
2014 - 2015 TCSA Production ceased in January 2014 when the mining contract expired. Failure to agree on a possible extension with the contractor led to the operation being placed under care and maintenance in February 2014.
2015 - 2018 Exxaro Coal Central (ECC) TCSA became ECC after being taken over by Exxaro in August 2015. Tumelo remained under care and maintenance.
2019 ECC Mmakau Mining recommissioned the operation in 2019 with first coal mined in April.

Tumelo geology

Tumelo is to the north of the Smithfield Ridge on the north-eastern edge of the Springs-Witbank coalfield. The area is part of the Karoo basin with stratigraphy similar to that of other ECC operations, Dorstfontein and Forzando with subtle location-induced differences.

Six coal seams are developed in the area, named from the base up as S1, S2, S4L, S4U, S4A and S5. S1 is very thin, being only developed in the deepest part of the
palaeo-valley. The thickest average seam is the S2 (0.5m to 5.3m), developed mainly in a palaeo-valley where it is either thin or absent over the adjacent palaeo-ridges. S2 has been exploited since Tumelo production started in 2009. S4L is the most continuous and second-thickest seam while S4U is thin and has mostly been eroded. S4A is thin and patchily developed and S5 is only present in a topographically high area in the south east. The only economically exploitable seam is S2.

Figure 29: Tumelo cross-section

Late Jurassic dolerite sills and dykes occur in the Tumelo area. The intrusions resulted in displacement of the various seams and devolatilisation of extensive areas of coal. The geological complexity and associated challenges are proactively managed by extensive infill drilling, downhole wireline logging for better contact definition and seam correlation as well as surface mapping, particularly of basement outcrops. This information is captured in a structural model, together with potential risks captured in a GIS-based risk and opportunity domain analysis (RODA), allowing for a more integrated approach to risk management.

Tumelo Resource evaluation

All exploration boreholes are logged and sampled by qualified geologists, aligned with Exxaro logging and sampling standards and standard operating procedures. Samples are selected according to seam boundaries, visual variation in the vitrinite content, assisted by density logs, and non-coal material present in the seam boundaries. The geologist takes cognisance of the borehole purpose and drilling conforms to ECC standards.

ECC's sampling governance and chain of custody requires that each sample to be submitted to the laboratories is accompanied by a sample submission list that also serves as a sample advice sheet with instructions for analysis. The laboratory is notified of samples that are ready for collection. On collection, the laboratory representative cross-checks all samples against the submission list to confirm the names and number of samples they are receiving. All submission lists are managed in duplicates with signed copies scanned and saved electronically in the geology server.

All geological core sample are sent to the laboratory for coal quality analysis. Two major laboratories have been used at Tumelo: Australian Laboratory Services (ALS) and Societe Generale de Surveillance (SGS) with SANAS accreditation (T0611 and T0815 respectively). ISO and South African National Standards (SANS) have a standard set of tests and methods used for coal analysis by South African laboratories. These laboratories have committed to assuring the quality of results provided to the customer by ensuring quality assurance, quality control, data validation and proficiency testing procedures are observed.

Table 73: Tumelo Coal Resource reporting criteria

Thickness cut-off (reporting and
extraction considerations)
Quality cut-offs (adb) Geological loss*
Underground ≤1.2M  

DAFV ≤24%

Raw ash ≥50%

  10% – 50%
* A 10% standard geological loss is applied but may vary based on consideration of structural complexity (dolerite sill breakthrough - 50% loss within determined spatial extent), seam gradient (>4 degrees - 50% loss) and dolerite sill proximity to seam (25% loss). A 15% geological loss is applied (weighted average of the various risk domains).

Table 74: Tumelo Coal Resource estimation criteria

Item     Description
Database Borehole database     Sable Data Warehouse
  Data datum Cape LO29
  Number of boreholes used for Resource estimation 103 of 132 boreholes in the database with washability data
  Validation The laboratory conducts data validation on samples. In the Sable Database Warehouse, additional validations are conducted and corrected. Data is exported from Sable into csv files where additional checks are conducted in Excel
  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 RD and length of each sample. This is done in Geovia MinexTM
Model Previous model date     January 2010 in Stratmodel
  Last model update January 2017
  Geological modelling software Geovia MinexTM
  Estimation technique Growth algorithm – general purpose gridding
  Grid mesh size 25m x 25m
  Scan distance 2 000m
  Data boundary 200m
  Model build limits Upper: limit of weathering and topography/collarLower: basement/Dwyka
  Model outputs Roof, floor and thickness grids generated for structure.Raw quality and washability grids
  Changes to modelling process Change in modelling package from Stratmodel to Geovia MinexTM

Table 75: Tumelo Coal Resource classification criteria

Category Type of boreholes Borehole spacing Structurally complex areas BH/ha
Measured Cored boreholes with applicable coal qualities 0m - 350m Structural complexity and coal variability - additional infill drilling 0.30
Indicated Cored boreholes with applicable coal qualities 350m - 500m Structural complexity and coal variability - additional infill drilling 0.20
Inferred Cored boreholes with applicable coal qualities 500m - 1 000m Structural complexity and coal variability - additional infill drilling 0.11

Table 76: Tumelo Coal Resource statement

Category 2019 
in tonnes 
  Reason for change  
Measured 8.4    8.7    0.3    (3)   Mining  
Indicated 0.2    0.2    —    —   
Inferred 1.8    1.8    —    —   
Total Coal Resources 10.4    10.7    0.3    (3)  

Rounding of figures may cause computational discrepancies.

  • All changes more than 10% are explained.
  • Mining method: underground (UG).
  • Figures reported at 100% irrespective of percentage attributable to Exxaro.
  • Tonnages quoted in metric tonnes and million tonnes abbreviated as Mt. Coal Resources quoted as mineable tonnes in-situ (MTIS) and refer to remaining Resources after 31 December 2019 and 31 December 2018.
  • Coal Resources reported on a MTIS basis.
  • Cut-offs applied as per Resource reporting criteria table.
  • Coal Resources quoted inclusive of Coal Reserves.

Table 77: Tumelo RPEEE considerations

Item Criteria Considered Comment
Geological data Data validated and signed off by competent person   Yes   Geological structure and depositional extent, seam thickness >1.2m (UG), <50% ash content, >24% DAFV. Coal qualities reported on an air-dry basis
Geological model 2017 geological model considered and signed off   Yes  
Structural model Structural model considered and signed off   Yes  
Mining Mining assumptions considered and defined   Yes   UG areas defined and aligned with exploitation strategy
Assurance Policy-driven governance, internal and external audits   Yes   In place, internal review 2012
Economic evaluation Concept-level exploitation with economic and mining assumptions, including geotechnical and geohydrological assumptions   Yes   Only approved economic assumptions and parameters applied
Environmental Reasonable demonstration that environmental approvals can be obtained within the context of local, regional and national governmental legislation   Done   Areas where there is reasonable expectation that mining will not be permitted are considered, such as wildlife sanctuary, river and streams, historic sites and monuments. Environmental and social concept assessments have been completed
Tenure Only areas in acceptable prospecting and mining rights. In areas adjacent to existing rights where legal section application is pending with reasonable expectation of approval   Yes   MR/PR licences are valid. Extensions or annexations will be lodged as necessary
Infrastructure Assumptions used should be reasonable and within known/assumed tolerances or have examples of precedence   Done   Current infrastructure
Market Market(s) identified form part of an existing operation market strategy or potential market for which there is a conceptual market study   Done   Operational strategies aligned with existing markets

Tumelo known risks

The Tumelo mining right expired on 10 December 2015 and a renewal application was lodged with the Department of Minerals and Energy on 29 July 2015, approved in early 2019 and executed in August 2019.

Boreholes received from third parties and drilled between 1990 and 1991 lack wash information for specific fractions. A limited amount of drilling is required to address this data gap. The Coal Resources estimates are received from Mmakau Mining.

Tumelo excellence

Continuous reviews of geological information and economic viability by Mmakau Mining lead to the mining of 0.3Mt during the reporting year.