• Operations

Reserves and Resources

The 2022 Mineral Resource update, effective December 25, 2021, incorporates production since the 2019 Mineral Resource was completed. The 2022 mineral resources for the Karowe Mine have been classified as either Indicated or Inferred Mineral Resources, according to CIM Guidelines. Mineral Resources reported are inclusive of those portions of the Mineral Resources that have been converted to Mineral Reserves. Mineral Resources reported are exclusive of stockpiles which are reported in the Mineral Reserve.

Mineral Resources Karowe Mine 2022 Mineral Resource Statement
(effective date of December 25, 2021)

Classification

Resource

Tonnes (Mt)

Carats (Mcts)

Grade (cpht)

Indicated

South – M/PK(S)

23.18

2,495

10.8

South – EM/PK(S)

20.37

4,310

21.2

Centre

2.12

321

15.1

North

0.76

81

10.6

Total Indicated

46.43

7,207

15.5

Inferred

South – M/PK(S)

0.31

33

10.5

South – EM/PK(S)

4.19

877

20.9

South – KIMB3

0.94

103

10.9

Centre

0.99

127

12.9

North

0.47

53

11.2

Total Inferred

6.9

1,192

17.3

Notes:

  1. 1. Prepared by Cliff Revering, P. Eng. of SRK Consulting
  2. 2. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. All numbers have been rounded to reflect accuracy of estimate.
  3. 3. Mineral Resources are in-situ Mineral Resources and are inclusive of in-situ Mineral Reserves.
  4. 4. Mineral Resources are exclusive of all mine stockpile material.
  5. 5. 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 the current configuration of the Karowe Mine process plant.
  6. 6. 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.
  7. 7. The base of the South Lobe Indicated Resource is 250masl, the base of the Inferred Mineral Resource is 66masl for the South Lobe. The base of the Centre and North Lobe Indicated Resource is 745masl.
  8. 8. Average diamond value estimates are based on 2019 diamond sales data provided by the Company.
  9. 9. Mineral Resources have been estimated with no allowance for mining dilution and mining recovery.

A consolidated open pit and underground mine plan was developed to extract the economic portions of Karowe Mine Indicated Mineral Resources plus stockpiled ore. The mine plan includes extraction of three adjacent lobes of kimberlite. The South Lobe is planned to be mined through a combination of open pit and underground mining methods. The North and Centre Lobes are planned for extraction by open pit mining methods only. All Mineral Reserves are classified as Probable.

The Qualified Person preparing the Mineral Reserve Estimate, Gord Doerksen, P. Eng., did not identify any extraordinary risk, including legal, political or environmental risks that would materially affect potential Mineral Reserves development. The effective date of this Mineral Reserve Estimate is December 25, 2021.

Mineral Reserves Karowe Mine 2022 Mineral Reserve Estimate
(effective date of December 25, 2021)

Lobe

Reserve
Category

Ore (Mt)

Carats
(‘000s ct)

Diluted Grade
(cpht)

LOM Diamond
Price ($/ct)

Open Pit

North

Probable

0.4

33

9.4

$221

Centre

Probable

2

299

15.1

$349

South – EM/PK(S)

Probable

1.8

456

25.2

$777

South – M/PK(S)

Probable

5.5

581

10.5

$631

Open Pit

Total

9.7

1,368

14.2

$608

Underground

South – EM/PK(S)

Probable

18.3

3,334

18.2

$777

South – M/PK(S)

Probable

19.1

1,892

9.9

$631

Underground

Total

37.4

5,226

14

$724

Stockpiles

Life of Mine

Probable

5

256

5.1

$495

Mixed Stockpile

Probable

3.8

451

11.9

$434

Stockpile

Total

8.8

706

8

$456

Combined

All

Total

55.9

7,301

13.1

$676

Notes:

  1. 1. Prepared by Brandon Chambers, P.Eng. under the supervision and sign-off by Qualified Person Gord Doerksen, P.Eng., both of JDS Energy & Mining Inc.
  2. 2. CIM Guidelines and Definitions were followed for Mineral Reserves.
  3. 3. Mineral Reserves are estimated at a cut-off value of US$33/t based on an OP and UG mining cost of US$11/t, a processing cost of US$15/t and a G&A cost of US$7/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 Lob
  4. 4. UG dilution included in the Reserve was estimated and revised in 2021 from the 2019 FS and
     
    a.1.0 m of zero-grade overbreak from stoping adjacent to the granite host rock;
    b.2.7 Mt of zero-grade overbreak from stoping adjacent to sedimentary rocks (based on geomechanical modelling);
    c.Inclusion of inferred KIMB3 kimberlite which for reporting and economic modelling purposes is treated as zero-grade dilution in the mine plan.
     
  5. 5. The bottom elevation of the Probable Reserve is 310 masl.
  6. 6. Mineral Reserves 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 the current configuration of the Karowe Mine process plant.
  7. 7. Diamond valuation was derived from historical sales adjusted for current and estimated future values.
  8. 8. Tonnages are rounded to the nearest 100,000 tonnes; diamond grades are rounded to one decimal place to properly reflect the Reserve estimate accuracy.
  9. 9. Tonnage and grade measurements are in metric units; contained diamonds are reported as thousands of carats.
  10. 10. Stockpile Reserves are not included in the Karowe Mineral Resource Estimate, which covered only in-situ mineralized material.
  11. 11. Stockpile Reserves are based on surveyed volumes and block model grades.
  12. 12.All numbers have been rounded to reflect accuracy of estimate.

For additional details on the extent to which the Mineral Resources and Mineral Reserves may be materially affected by metallurgical, environmental, permitting, legal, title, taxation, socio-economic, marketing, political and other relevant issues, please see the section titled “Risks and Uncertainties” contained in this AIF.