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Contents

Free State

Geology: The Harmony Free State Operations are located on the south-western corner of the Witwatersrand Basin, between the towns of Allanridge, Welkom, Theunissen and Virginia. The basin, situated on the Kaapvaal Craton, has been filled by a 6-kilometre thick succession of sedimentary rocks, which extends laterally for hundreds of kilometres.

The Free State goldfield is divided into two sections, cut by the north-south striking De Bron Fault. This major structure has a vertical displacement of about 1 500m in the region of Bambanani, as well as a lateral shift of 4km. This lateral shift can allow a reconstruction of the orebodies of Unisel to the west of the De Bron and Merriespruit to the east. A number of other major faults (Stuirmanspan, Dagbreek, Arrarat and Eureka) lie parallel to the De Bron Fault.

To the west of the De Bron, the currently operating mines are Target, Tshepong, Phakisa, Nyala, Unisel, Brand, Bambanani and Joel operations. Dips are mostly towards the east, averaging 30 degrees but become steeper approaching the De Bron Fault. To the east of the fault lie Merriespruit 1 and 3, Harmony 2 and Masimong mines. These mostly dip towards the west at 20 degrees, although Masimong is structurally complex and dips of up to 40 degrees have been measured. Between these two blocks lies the uplifted horst block of West Rand Group sediments with no reef preserved.

The western margin area is bound by synclines and reverse thrusts faults and is structurally complex. Towards the south and east, reefs sub-crop against overlying strata, eventually cutting out against the Karoo to the east of the lease area.

Most of the Ore Resource tends to be concentrated in reef bands located on one or two distinct unconformities. A minority of the Mineral Resource is located on other unconformities. Mining that has taken place is mostly deep-level underground mining, exploiting the narrow, generally shallow dipping tabular reefs.

The Basal Reef is the most common reef horizon and is mined at all shafts except Target and Joel. It varies from a single pebble lag to channels on more than 2m thick. It is commonly overlain by shale, which thickens northwards. Tshepong has resorted to undercutting of its mining panels to reduce the effect of shale dilution.

The second major reef is the Leader Reef, located 15-20m above the Basal Reef. This is mostly mined at the shafts to the south – Unisel, Harmony 2, Merriespruit 1 and Merriespruit 3. Further north, it becomes poorly developed with erratic grades. The reef consists of multiple conglomerate units, separated by thin quartzitic zones, often totalling up to 4 metres thick. A selected mining cut on the most economic horizon is often undertaken.

The B Reef is a highly channelised orebody located 140m stratigraphically above the Basal Reef. Because of its erratic nature, it has only been mined at Masimong and Tshepong. Within the channels, grades are excellent, but this falls away to nothing outside of the channels. Consequently, both shafts have undertaken extensive exploration to locate these pay channels.

The A Reef is also a highly channelised reef, located some 40m above the B Reef. This is currently only mined at Harmony 2 and Brand, although an extensive channel lies along the western margin from Nyala to Lorraine. It consists of multiple conglomerate bands of up to 4m thick and a selected mining cut is usually required to optimise the orebody. Joel Mine, located 30km south of Welkom, is the only Harmony Free State operation to mine the Beatrix Reef. This varies from a single-pebble lag to a multiple conglomerate, often showing mixing of the reef with some of the overlying lower grade VS5 (mixed pebble conglomerate) material. None of the other reefs are present this far south, having sub-cropped against the Beatrix Reef.

The Target operations are located at the northern extent of the Free State Goldfields, some 20km north of Welkom. The reefs currently exploited are the Elsburg-Dreyerskuil conglomerates, which form a wedge-shaped stacked package, comprising 35 separate reef horizons, often separated by quartzite beds. The Elsburg Reefs are truncated by an unconformity surface at the base of the overlying Dreyerskuil Member. Below the sub-crop, the Elsburg dips steeply to the east, with dips becoming progressively shallower down dip. Close to the sub-outcrop, the thickness of the intervening quartzites reduces, resulting in the Elsburg Reefs coalescing to form composite reef packages that are exploited by massive mining techniques at the Target mine. The Dreyerskuil also consists of stacked reefs dipping shallowly to the east. These reefs tend to be less numerous, but more laterally extensive than the underlying Elsburg Reefs.

Free State – Gold mineral resources

 Measured IndicatedInferred Total
OperationsTonnes
(Mt)

g/t
Gold
(000kg)
Gold
(000oz)
Tonnes
(Mt)

g/t
Gold
(000kg)
Gold
(000oz)
Tonnes
(Mt)

g/t
Gold
(000kg)
Gold
(000oz)
Tonnes
(Mt)

g/t
Gold
(000kg)
Gold
(000oz)
Underground                
Bambanani11.411.201274 0876.49.67621 9933.89.02341 10121.610.362237181
Joel4.36.44288953.96.822785512.36.50802 580 20.56.551354330
Masimong14.07.551063 40114.96.51973 128100.36.6967121 576129.26.7687428 105
Phakisa                
  Phakisa0.29.7226522.112.292728 74557.87.0240513 03680.18.4867921 846
  Nyala4.46.91319853.94.76185928.35.91491 577
Total4.67.03331 05026.011.172909 33757.87.0240513 03688.48.2472823 423
Target*6.39.81621 99113.97.651063 4125.26.26321 04325.47.902006 446
Tshepong14.011.031544 94914.311.321625 21113.88.851223 92242.110.4243814 082
Virginia                
  Harmony 210.24.75481 5597.13.302475777.13.672829 08294.43.7635411 398
  Merriespruit 18.55.20451 4213.85.252063539.64.191665 33451.94.432317 390
  Merriespruit 38.85.25461 4912.84.91144367.04.082991718.64.76892 844
  Unisel11.25.56621 98912.04.7356182820.64.6597 3 08643.84.902156 903
  Brand 34.16.78288924.16.912991610.05.15511 65018.25.911083 458
Total42.85.352297 35229.84.771434 572154.34.0562520 069226.94.3999731 993
Total Underground   97.4 7.5473923 725109.28.1288728 508347.55.671 96963 327554.1 6.493 595115 560
Surface                
  Phoenix130.80.27361 1485.30.26144136.10.27371 192
  St Helena289.60.25722 327289.60.25722 327
  Other421.80.22932 984142.00.33471 500195.20.23451 444759.00.241855 928
Total surface842.20.24201 142.00.33471 500200.50.23461 4881 184.70.252949 447
GRAND TOTAL939.6 94030 184251.2 93330 008548.0 2 01564 8151 738.8 3 889125 007

* Target’s mineral resources are stated as work in progress – the process has been independently reviewed by SRK.

Modifying factors

OperationsMCF (%)SW (cm)MW (cm)PRF (%)
Bambanani    7820021896
Joel    9315019896
Masimong    6713015495
Phakisa    8110012995
Nyala8715019194
Tshepong6510514297
Harmony 26915417895
Merriespruit 17516220595
Merriespruit 3 6721824695
Unisel80175193 95
Brand 3 9419322996
  • MCF = Mine call factor
  • MW = Milling width
  • SW = Stoping width
  • PRF = Plant recovery factor
OperationsMCF (%)Dilution (%)PRF (%)
Target   95596
Phoenix100_47
St Helena100_47
Other100_47
  • MCF = Mine call factor
  • PRF = Plant recovery factor
 
Free State – Gold mineral resources [map]

Free State – Gold ore reserves

 Proven ProbableTotal
OperationsTonnes
(Mt)
Grade
g/t
Gold
(000kg)
Gold
(000oz)
Tonnes
(Mt)
Grade
g/t
Gold
(000kg)
Gold
(000oz)
Tonnes
(Mt)
Grade
g/t
Gold
(000kg)
Gold
(000oz)
Underground            
Bambanani3.5  8.48309651.210.90 134204.79.09431 385
Joel0.9  5.7451612.25.52134043.15.5818565
Masimong4.5  5.20247511.4 5.2772335.95.2231984
Phakisa            
  Phakisa0.3  5.38 14320.18.121635 23420.48.081645 277
  Nyala0.1  4.011130.03.3750.13.82118
  Total0.4  4.9825620.18.111635 23920.58.051655 295
Target*4.86.10299429.0 5.60501 61713.85.77792 559
Tshepong12.85.30682 18411.5 5.78662 13024.35.531344 314
Virginia            
  Harmony 20.93.56 3 1030.13.2891.03.533112
  Merriespruit 11.24.5561830.6 4.452861.84.528269
  Merriespruit 30.93.6931020.2 2.80 1161.13.544118
  Unisel3.04.95 15 4821.84.8592764.84.9124758
  Brand 30.63.92 2700.14.421200.74.02390
Total6.64.4329 9402.84.56 134079.44.47421 347
Total Underground33.55.771875 99948.26.7532510 45081.76.2751216 449
Surface            
Free State Surface           
  Phoenix130.80.27361 148130.80.27361 148
  St Helena289.6 0.25722 326289.60.25722 326
  Other421.80.22932 985101.70.26 26845523.50.231193 830
Total surface842.20.24 2016 499101.70.2626845943.90.242277 304
GRAND TOTAL875.7 38812 458149.9 35111 2951 025.6 73923 753

* Target’s ore reserves are stated as work in progress – the process has been independently reviewed by SRK.

Free State – Uranium mineral resources

 Measured IndicatedInferred Total
 Tonnes  U3O8 U3O8Tonnes  U3O8 U3O8Tonnes  U3O8 U3O8Tonnes  U3O8 U3O8 
Operations(Mt)kg/t(M kg)(M lbs)(Mt)kg/t(M kg)(M lbs)(Mt)kg/t(M kg)(M lbs)(Mt)kg/t(M kg)(M lbs)
Surface358.80.09337236.50.104868.40.07511463.70.094291
Bambanani: grade tonnage curve (measured and indicated resources) [graph]
 
Joel: grade tonnage curve (measured and indicated resources) [graph]
 
Masimong: grade tonnage curve (measured and indicated resources) [graph]
 
Phakisa: grade tonnage curve (measured and indicated resources) [graph]
 
Nyala: grade tonnage curve (measured and indicated resources) [graph]
 
Tshepong: grade tonnage curve (measured and indicated resources) [graph]
 
Harmony 2:: grade tonnage curve (measured and indicated resources) [graph]
 
Merriespruit 1: grade tonnage curve (measured and indicated resources) [graph]
 
Merriespruit 3: grade tonnage curve (measured and indicated resources) [graph]
 
Unisel: grade tonnage curve (measured and indicated resources) [graph]
 
Brand 3: grade tonnage curve (measured and indicated resources) [graph]
 
Virginia operations: Harmony 2, Merriespruit 1, Merriespruit 3 and Unisel shafts (Leader reef) [map]

Virginia operations: Harmony 2 shaft (A Reef) [map]

Tshepong shaft, Phakisa shaft [map]

Brand 1 and 3 shafts, Bambanani and Unisel shafts [map]

Merriespruit 1 and 3, Harmony 2 and Masimong 4 and 5 shafts (Basal Reef) [map]

Joel (Beatrix Reef) [map]

Target Mine (Elsburg and Dreyerskuil Reefs) [map]

Target mine resource blocks (Elsburg and Dreyerskuil Reefs) [map]

Harmony Annual Report 2009