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Our Mines

Our portfolio incorporates major underground pipe mines and a large high-volume open cast mine

  • Koffiefontein

    Koffiefontein is one of the world’s top diamond mines by average value per carat

  • Koffiefontein

    Koffiefontein is one of the world’s top diamond mines by average value per carat

  • Koffiefontein

    Koffiefontein is one of the world’s top diamond mines by average value per carat


Mining first started at Koffiefontein over 140 years ago and the mine’s remarkable longevity is a testament to its quality.

Koffiefontein is a low grade deposit, but this is countered by the very high value of its diamond production. The mine produces white stones of exceptional quality, a regular proportion of which are of between 5 and 30 carats, and occasional fancy pink diamonds. In 1994, a 232 carat diamond was recovered at Koffiefontein, being the largest rough diamond ever produced by the mine.

Petra’s expansion plan at Koffiefontein is expected to increase production from 51,173 ctpa in FY 2017 to approximately 85,000 ctpa steady state (underground only). The Company’s current mine plan has a life to 2031.


Key Facts

Location Free State Province, South Africa
Size of kimberlite pipe at surface 11ha
Mine start date 1870
Acquisition by Petra Diamonds July 2007
Acquisition cost ZAR 1.9m
Ownership Petra Diamonds: 74%1
Kago Diamonds (Pty) Ltd: 14%
Itumeleng Petra Diamonds Employee Trust: 12%
Total Resources
(inclusive of Reserves)
5.75 Mcts
Current depth of Resources 720m
Mining Method Sub level and block cave
Depth of current mining 600m
Mine Plan To 2027
Potential Mine Life +20 years

 1. Refer to Petra’s ‘Effective Interest in Mines’ in the following document: Analyst Guidance Explanatory Notes.


Diamonds were first discovered on the Koffiefontein farm in 1870. Mining started in the form of small claims that were later amalgamated into Koffiefontein Mine Limited.

De Beers acquired control of Koffiefontein Mine Limited in 1911. Mining operations were then continuous until the advent of the Great Depression in 1932 when work was suspended. Between 1950 and 1953, a prospecting shaft was sunk which was followed by limited production. The mine was reopened in 1970 and preparations for increased production were completed in August 1971. Immediately after completing the preparations, production from the open pit commenced and proceeded to a depth of 270 metres.

Underground development started in 1974 through a sampling programme. Underground production briefly took place in 1982 but ceased soon thereafter due to the 1981 slump in the diamond market, before resuming again in March 1987. In February 2006, De Beers ceased mining when the old order mining right for Koffiefontein expired and in July of that year Petra commenced operating the mine under care and maintenance conditions, before completing the acquisition of the mine in July 2007.

From its first beginnings, Koffiefontein has been noted for the excellent quality of its diamonds, with Edwin Streeter commenting in 1898 that its diamonds were of the “first water” (meaning of exceptional clarity).

Reserves & Resources

Category Tonnes (millions) Grade (cpht) Contained Diamonds (Mcts)
Probable 6.7 8.5 0.57
Sub-total 6.7 8.5 0.57
Indicated 28.1 5.5 1.53
Inferred 126.6 3.3 4.22
Sub-total 154.7 3.7 5.75

1. Resource bottom cut-off (Koffiefontein underground and Ebenhaezer) lifted to 1.15 mm (previously 0.5mm).
2. Resource bottom cut-off (Eskom tailings): 1.0mm.
3. Reserve bottom cut-off: 1.15mm.
4. Changes in Resource afigures due to mining depletions and re-estimation of the main pipe below 49L to 74L, incorporating new bulk sampling from SLC ring blasting and development.
5. Ebenhaezer removed from Reserve – no plans to re-start production.
6. US$/ct values of 525-550 for ROM guided for FY 2018, based on sales values and production size frequency distributions.

FY 2017 Results

Unit FY 2017 FY 2016 Variance
Revenue US$M 28.4 25.7 +11%
Diamonds sold Carats 56,068 55,500 +1%
Average price per carat US$ 506 462 +10%
ROM Production
Tonnes treated Tonnes 667,821 681,344 -2%
Diamonds produced Carats 51,173 50,825 +1%
Grade Cpht 7.7 7.5 +3%
Tailings / Ebenhaezer Production
Tonnes treated Tonnes 446,854
Diamonds produced Carats 11,365
Grade Cpht 2.5
Total Production
Tonnes treated Tonnes 667.821 1,128,198 -41%
Diamonds produced Carats 51,173 62,190 -18%
On-mine cash cost per tonne treated ZAR 532 317 +68%
Expansion Capex US$M 13.3 24.6 +46%
Sustaining Capex US$M 5.5 2.9 -13%
Total Capex US$M 18.8 27.5 -32%

ROM production at Koffiefontein increased 1% to 51,173 carats (FY 2016: 50,825 carats), but was below expectations due to challenges encountered with the SLC ore handling infrastructure. This work was hampered by difficult ground conditions in both the second crusher chamber and decline ramp, restricting the ability to transport material and equipment to the working levels. The second crusher, which aims to alleviate ground handling constraints, will be fully operational in Q2 FY

Overall production was down 18% to 51,173 carats (FY 2016: 62,190 carats), as production from the satellite Ebenhaezer pit ceased in FY 2016, as planned, together with the challenges detailed above.

Mine Plan

The Company’s expansion plan at Koffiefontein is expected to increase production from 51,173 ctpa in FY 2017 to approximately 85,000 ctpa steady state (underground only). The Company’s current mine plan has a life to 2031. Koffiefontein’s expansion programme entails the development of an SLC from 560mL to 600mL, before putting in place a new block cave at approximately 720mL. However, the Company’s ongoing review of its future capital requirements may result in a continuation of the SLC to deeper levels, in preference to the installation of the block cave currently included in the Company’s plans.

Click on schematic to enlarge.

Mining Right

Blue Diamond Mines (‘‘BDM’’) holds a valid and unencumbered new order mining right dated 2 February 2007 (the ‘‘Koffiefontein Mining Right’’), granted to it pursuant to section 23 of the MPRDA. The Koffiefontein Mining Right was duly notarially executed by the DMR and registered in the Mineral & Petroleum Titles Registration Office.

A renewal of the Koffiefontein Mining Right was notarially executed by the DMR on 26 April 2017 and, pursuant to such renewal, the Koffiefontein Mining Right confers on BDM the exclusive right to mine for diamonds in relation to the areas it refers to until 23 February 2047.

Section 2 of the Royalty Act requires BDM to pay the South African Government a royalty for minerals recovered under the Koffiefontein Mining Right. Pursuant to section 4 of the Royalty Act, the royalty is to be paid on gross sales in accordance with a defined formula set out in the Royalty Act. The formula applicable to rough diamonds is as follows: 0.5% + (earnings before interest and taxes as defined in Section 5 of the Royalty Act / (gross sales x 9) x 100) but not exceeding 7%.

In addition, South Africa has a rough diamond export levy requirement of 5% as set out in section of the Diamond Export Levy Act 15 of 2007 (“Export Levy Act”). Producers are however exempt from this levy in respect of production that is exported provided that a certain percentage of their production is sold to local diamond beneficiation licence holders, on the basis more fully set out in sections 7, 8 and 9 of the Export Levy Act.

BDM is also subject to corporate tax in South Africa at the rate of 28% in terms of section 5 and other provisions of the Income Tax Act 58 of 1962.

There are no fiscal stabilisation provisions in place in relation to Koffiefontein Diamond Mine.


  • July 2007 Acquisition by Petra
  • 51,173 carats FY 2017 Production
  • 5.8m carats Total diamond resource


Koffiefontein Diamonds

The high quality white diamonds for which Koffiefontein is known

GJG_055Koffiefontein occasionally produces pink diamonds