Reserves and Resources

Mineral Resources

In support of the FS an updated Mineral Resource Estimate, Karowe Mine AK06 Updated Mineral Resource Statement reflecting depletion as of June 30, 2019, was prepared by SRK. The updated resource estimate is based on historical evaluation data combined with new deep drilling data from the FS study programme. New sampling results (microdiamond, bulk density, and petrography) have been fully integrated with recent deep drilling and historical drilling.  Separate size distribution and value models have been developed from production data for the two dominant domains within the South Lobe, the EM/PK(S) and M/PK(S).  Grade and tonnage estimates are based on an updated and revised geological model, an updated recoverable grade model based on Karowe processing plant recoveries,and updated average price per carat values. The 2019 mineral resources for Karowe, have been classified as either Indicated or Inferred mineral resources, according to CIM Definition Standards for Mineral Resources and Mineral Reserves (CIM, 2014).  Mineral Resources reported are inclusive of those portions of the Mineral Resource that have been converted to Mineral Reserves and have an effective date of July 1, 2019. 

Karowe Mine AK06 Updated Mineral Resource Statement

Classification

Domain

Volume
(Mm3)

Tonnes
(Mt)

Density
(t/m3)

Carats
(Mcts)

Grade
(cpht)

Average
US$/ct

Indicated

 

 

South M/PK(S)

9.40

27.81

2.96

3.01

10.8

$631

South EM/PK(S)

7.62

22.10

2.90

4.68

21.2

$777

Centre

1.28

3.28

2.57

0.50

15.1

$367

North

0.44

1.08

2.45

0.13

11.8

$222

TOTAL INDICATED

18.74

54.27

2.90

8.32

15.3

$690

 

Inferred

 

South M/PK(S)

0.10

0.31

3.05

0.03

10.5

$631

South EM/PK(S)

1.40

4.18

2.97

0.87

20.9

$777

South_KIMB3

0.32

0.94

2.94

0.10

10.9

$631

TOTAL INFERRED

1.82

5.42

2.97

1.01

18.6

$750

Notes:

  • Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. All numbers have been rounded to reflect accuracy of the estimate.
  • Mineral Resources are in-situ Mineral Resources and are inclusive of in-situ Mineral Reserves.
  • Mineral Resources are exclusive of all mine stockpile material.
  • Mineral Resources are quoted above a +1.25 mm bottom cut-off and have been factored to account for diamond losses within the smaller sieve classes expected within a commercial process plant.
  • Inferred Mineral Resources are estimated on the basis of limited geological evidence and sampling, sufficient to imply but not verify geological grade and continuity. They have a lower level of confidence than that applied to an Indicated Mineral Resource and cannot be directly converted into a Mineral Reserve.
  • Average diamond value estimates are based on value models generated from production and sales data from Karowe operations as provided by Lucara Diamond Corporation.
  • Mineral Resources have been estimated with no allowance for mining dilution and mining recovery.

Mineral Reserves

The Karowe Mineral Reserve Estimate for the FS was compiled by QP Gord Doerksen, P.Eng. and has an effective date of September 26, 2019 and is summarized in Table 8.

Karowe Mine AK06 Mineral Reserve Statement

Lobe - Type

Classification

Ore
(Mt)

Diluted Grade
(cpht)

Contained Carats
('000s ct)

Price
(US$/ct)

Open Pit

     

North

Probable

0.6

10.0

56

222

Centre

Probable

3.2

15.1

478

349

South – EM/PK(S)      

Probable

3.6

23.9

850

777

South – M/PK(S)

Probable

10.2

10.8

1,098

631

Open Pit

Total

17.4

14.2

2,481

618

Underground

     

South – EM/PK(S)

Probable

16.3

19.9

3,246

777

South – M/PK(S)

Probable

17.1

10.6

1,807

631

Underground

Total

33.5

15.1

5,053

725

Stockpiles

     

North

Probable

0.4

12.7

51

222

Centre

Probable

0.4

12.8

54

349

South – M/PK(S)

Probable

1.6

9.5

151

631

Mixed

Probable

4.0

5.0

198

609

Stockpiles

Total

6.4

7.1

454

542

Combined

     

All

Total

57.3

13.9

7,988

681

1.

Prepared by Gord Doerksen, P.Eng. JDS Energy & Mining Inc.

2.

CIM definitions were followed for Mineral Reserves and the effective date of the Mineral Reserve is September 26 2019.

3.

Mineral Reserves are estimated at a cut-off value of US$31/t based on an OP and UG mining cost of US$9/t, a processing cost of US$16/t and a G&A cost of US$6/t. Process recovery of the diamonds was assumed to be 100% as the recoveries were included in the mineral resource block model assumptions and therefore have taken recoveries into account.  All of the kimberlite material in the South Lobe is above the cut-off value.

4.

Average diamond value estimates are based on value models generated from production and sales data from Karowe operations as provided by Lucara Diamond Corporation.

5.

Tonnages are rounded to the nearest 100,000 tonnes, diamond grades are rounded to one decimal place. Tonnage and grade measurements are in metric units; contained diamonds are reported as thousands of carats.          

Source: JDS (2019)