Open pit mining at Ebenhaezer, the satellite pipe at Koffiefontein

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Fissures

Overview

The fissure mine portfolio comprises three mines: Helam, Sedibeng and Star. The Sedibeng operation is an amalgamation of two mines: Messina and Dancarl. Helam is located 70km west of Rustenburg in the North West Province, Sedibeng is located 80km north-west of Kimberley in the Northern Cape Province and Star is located 40km south of Welkom in the Free State Province. The mines are renowned for the consistent production of high value diamonds.

In September 2012, Petra commenced a disposal process in respect of the Fissure Mines, as they are no longer core to the Group’s portfolio.

Key Facts
Location South Africa
Strike length of fissure at surface Helam: 6km
Sedibeng: 2.4km
Star: 4.5km
Mine start date Helam: 1933
Sedibeng: 1952
Star: 1952
Acquisition by Petra Diamonds May 2005 (further to merger with Crown Diamonds NL)
Ownership Helam: 74% Petra Diamonds, 26% Sedibeng Mining (Pty) Ltd
Sedibeng: 74.5% Petra Diamonds, 17.85% Sedibeng Mining (Pty) Ltd, 7.65% Bokone Properties (Pty) Ltd
Star: 74% Petra Diamonds, 26% Sedibeng Mining (Pty) Ltd
Operator Petra Diamonds
Total Resources
(Resources inclusive of Reserves)		 5.1 Mcts
Current depth of Resources 970m
Mining Method Helam & Sedibeng: Full shrinkage overhand stoping
Star: Underhand open stoping
Depth of current mining Helam: 750m
Sedibeng: 750m
Star: 620m
Mine Plan Helam: 19 years
Sedibeng: 10 years
Star: 14 years
Potential Mine Life +15 years
History

Helam, Sedibeng and Star are all well-established underground fissure mines which have been in operation for more than 50 years. Each mine exploits narrow diamondiferous kimberlite fissures using labour intensive mining methods.

Reserves & Resources

Fissure Mines combined (Helam, Sedibeng, Star)

Category Gross Net attributable
Tonnes (millions) Grade (cpht) Contained Diamonds (Mcts) Tonnes (millions) Grade (cpht) Contained Diamonds (Mcts)
Reserves
Proved 1.463 47.66 0.697 1.085 47.61 0.517
Probable 2.057 60.40 1.243 1.524 60.36 0.920
Sub-total 3.520 55.11 1.940 2.609 55.05 1.437
Resources
Measured 0.545 153.39 0.836 0.404 153.16 0.619
Indicated 0.810 186.61 1.512 0.600 186.45 1.119
Inferred 1.705 161.13 2.748 1.263 161.02 2.034
Total Resources inclusive of Reserves 3.060 166.49 5.096 2.267 166.35 3.772
  • Resource bottom cut-off: 1.0mm
  • Reserve bottom cut-off: 1.0mm
  • Measured Resources are classified as one level below current workings, or where a block is bounded above and below by current workings
  • Indicated Resources are classified as two levels below measured Resources
  • Inferred Resources are classified as three levels below Indicated Resources or inaccessible mined out areas, or as extensions along strike from existing Resource blocks where exploration information allows
  • Measured and Indicated Resources have been converted to Reserves by applying historically derived external dilution and in-stope loss factors to resource tonnages and grades
Sale of the Fissure Mines

Petra Diamonds has, along with its BEE partners, commenced a public disposal process in respect of its fissure mine operations, namely the Helam, Sedibeng and Star mines in South Africa.

Please click here for more information

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