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.

Our expansion plan at Koffiefontein will increase production from 55,500 ctpa in FY 2016 to ca. 95,000 ctpa by FY 2017 (underground only). Petra’s current mine plan has a life to 2025, but the residual resources at the mine indicate that the actual LOM could be in excess of 20 years.


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: 70%1 & 2
Re Teng Diamonds (Pty) Limited: 30%
Total Resources
(inclusive of Reserves)
6.65 Mcts
Current depth of Resources 720m
Mining Method Sub level cave
Depth of current mining 560m-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 7.6 8.1 0.62
Sub-total 7.6 8.1 0.62
Indicated 38.8 6.4 2.47
Inferred 113.2 3.7 4.20
Sub-total 152.0 4.4 6.67

1. Resource bottom cut-off (Koffiefontein underground and Ebenhaezer): 0.5mm.
2. Resource bottom cut-off (Eskom tailings): 1.0mm.
3. Reserve bottom cut-off: 1.15mm.
4. Changes in Reserve and Resource figures due to underground mining depletions on all mining blocks; depletions applied to Ebenhaezer pipe in accordance with the June 2016 Lidar Survey.

FY 2016 Results

Unit FY 2016 FY 2015 Variance
Revenue US$M 25.7 17.8 +44%
Diamonds sold Carats 55,500 46,033 +21%
Average price per carat US$ 462 386 +20%
ROM Production
Tonnes treated Tonnes 681,344 341,783 +99%
Diamonds produced Carats 50,825 27,756 +83%
Grade Cpht 7.5 8.1 -7%
Tailings / Ebenhaezer Production
Tonnes treated Tonnes 446,854 524,244 -15%
Diamonds produced Carats 11,365 17,628 -36%
Grade Cpht 2.5 3.4 -27%
Total Production
Tonnes treated Tonnes 1,128,198 866,027 +30%
Diamonds produced Carats 62,190 45,384 +37%
On-mine cash cost per tonne treated ZAR 317 303 +5%
Expansion Capex US$M 24.6 23.1 +7%
Sustaining Capex US$M 2.9 3.7 -22%
Total Capex US$M 27.5 26.8 +3%

Production increased 37% to 62,190 carats (FY 2015: 45,384 carats), due to an increase in ROM tonnes treated as the SLC project commenced ramping up to its planned throughput of 1.1 Mtpa.

AS the SLC was in the process of ramping up during Q4 FY 2016, the majority of production was sourced from the diluted 52 mL, resulting in grade underperformance. Grades are expected to increase in line with the FY 2017 guided mine plan.


Mine Plan

Our expansion plan at Koffiefontein will increase production from circa 62,190 ctpa in FY 2016 to circa 95,000 ctpa by FY 2017.  This initial mine plan extends to 2025, but the residual resources at the mine indicate that the actual LOM could be in excess of 20 years.

As at Finsch, we will be using the SLC mining method at Koffiefontein, before putting in place a new block cave. The SLC will be mined over three levels from 560 mL to 600 mL.  Production has now commenced on the 560 mL of the SLC.

Underground ROM throughput is expected to increase from 0.7 Mt in FY 2016 to 1.1 Mt by FY 2017 at a grade of ca. 8 cpht.


 Koffiefontein schematic July 2015

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.

The Koffiefontein Mining Right confers on BDM the exclusive right to mine for diamonds in relation to the areas it refers to until 1 February 2017. Pursuant to the MPRDA, the Koffiefontein Mining Right is renewable (for periods of up to 30 years for each renewal) on the basis more fully set out in section 24 of the MPRDA.

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
  • 62,190 carats FY 2016 Production
  • 6.7m carats Total diamond resource


Koffiefontein Diamonds

The high quality white diamonds for which Koffiefontein is known

GJG_055Koffiefontein occasionally produces pink diamonds