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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.

FY 2021 production at Koffiefontein totalled 59,151 carats.


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)
5.31 Mcts
Current depth of Resources 720m
Mining Method Sub level and block cave
Depth of current mining 600m

 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 2.3 8.2 0.19
Sub-total 2.3 8.2 0.19
Indicated 14.6 7.6 1.11
Inferred 124.1 3.3 4.14
Sub-total 138.7 3.8 5.25

1. Resource bottom cut-off (Koffiefontein underground and Ebenhaezer): 1.15mm.
2. Reserve bottom cut-off: 1.15mm.
3. Main Pipe resources above 490L are remnants of the front cave mining block and include external waste. A portion of this remnant Resource reports into the current caving operations as low grade dilution.
4. Resources below 490L are stated as in situ.
5. The Eskom Tailings Mineral Resource has been removed following a donation of part of the Tailings Mineral Resource to the Koffiefontein Community Mining Primary Cooperative to promote artisanal small-scale mining in the area.
6. Remaining 56–60L sub-level cave Reserves are based on PCSLC simulations
7. US$/ct values of 470-520 for ROM, based on expected sales values (with reference to FY 2021 sales results and considering rough diamond prices recovering to levels before the COVID-19 pandemic) and production size frequency distributions.

FY 2021 Results

Unit FY 2021 FY 2020 Variance
Revenue US$M 28.0 25.7 +9%
Diamonds sold Carats 66,650 66,326 0%
Average price per carat US$ 419 387 +8%
ROM Production
Tonnes treated Tonnes 754,369 891,705 -15%
Diamonds produced Carats 59,151 69,077 -14%
Grade Cpht 7.8 7.7 +1%
Total Production
Tonnes treated Tonnes 754,369 891,705 -15%
Diamonds produced Carats 59,151 69,077 -14%
On-mine cash cost per tonne treated ZAR 651 510 28%
Expansion Capex US$M 0.6 2.7 -78%
Sustaining Capex US$M 1.1 1.1 0%
Total Capex US$M 1.7 3.8 -55%

ROM production totalled 59,151 carats (FY 2020: 69,077 carats), with ROM tonnage throughput down 15% on FY 2020 impacted by the significant rainfall experienced in Q3 FY 2021; overall carat production decreased by 14% with the average ROM grade remaining broadly flat at 7.8 cpht (FY 2020: 7.7 cpht).

Revenue increased 9% to US$28.0 million (FY 2020: US$25.7 million) for the Year, with an 8% increase in the average price per carat.

Mine Plan

FY 2021 Capex of US$1.7 million was spent on Stay in Business Capex.

FY 2022 Capex is guided at ca. US$1 – 3 million primarily relating to Stay in Business Capex.

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
  • 59,151 carats FY 2021 Production
  • 5.25m carats Total diamond resource


Koffiefontein Diamonds

The high quality white diamonds for which Koffiefontein is known

GJG_055Koffiefontein occasionally produces pink diamonds