Mining Goes Digital – Mueller et al. (Eds)
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
192
Evolving estimation techniques for an evolving world class
stratiform copper deposit at Kamoa-Kakula, Democratic
Republic of the Congo
G. Gilchrist
Ivanhoe Mines, Johannesburg, South Africa
ABSTRACT: The supergiant Kamoa-Kakula copper deposit is a greenfields discovery
made by Ivanhoe Mines in the Western Forelands area of the Central African Copperbelt in
the Democratic Republic of the Congo. Over ten years, progressive collection of significant
geological data and completion of nearly 1500 drillholes has led to an evolving modelling
methodology to include greater geological control, meet the needs of advancing mining studies, and to solve the difficulties posed by stratigraphic and mineralisation units extensive over
many kilometres but some only a few metres to tens of metres thick. Innovative modelling
routines, combining Datamine and Leapfrog functionality, has led to a full three dimensional
(3D) model honuouring vertical grade profiles, known controls on mineralisation, and accurately representing the geometry and relationships of numerous stratigraphic and mineralised
units. Information now captured in the model has aided mining and metallurgical optimisation, which has added significant value to the project economics.
1 INTRODUCTION
The Kamoa-Kakula copper deposit is a greenfields discovery made by Ivanhoe Mines in
the Western Forelands area of the Central African Copperbelt (CACB) in the Democratic
Republic of the Congo (DRC), discovered in an area previously considered unprospective for
large copper deposits just 25 km west of the Kolwezi Cu-Co district. Ten years later, nearly
1500 drillholes have defined the largest copper deposit ever discovered in Africa, extending
28 km north-south and 23 km west-east, and with characteristics similar to the Kupfeschiefer
copper deposits in Poland. At a 1% cut-off, the deposit boasts an Indicated Resource of
1387 Mt at 2.64% Cu and an Inferred Resource of 316 Mt at 1.76% Cu. Mine development
has commenced and the project has attracted international investment.
Since its discovery, mapping, geophysical surveys and a growing drillhole database have
allowed for significant advancements in the geological understanding of the deposit, in particular the controls on mineralisation. Traditionally, understanding geological processes is a
key focus during the exploration phase, but emphasis tends to shift to ensuring the geometry
is correct once resource estimation and mine planning commence. In the modelling approach
developed at Kamoa-Kakula, both the geological processes controlling mineralisation and
accuracy in geometry are combined to produce a high quality resource model. This is achieved
without making the model so complex that it is impractical to update on a regular basis.
2 GEOLOGY
2.1 Regional geology
The CACB is the world’s premier sediment-hosted copper province. It is contained in the
Katangan basin, an intracratonic rift that records onset of growth at ∼840 Ma and inversion at
© 2019 Taylor & Francis Group, London, ISBN 978-0-367-33604-2
192
Evolving estimation techniques for an evolving world class
stratiform copper deposit at Kamoa-Kakula, Democratic
Republic of the Congo
G. Gilchrist
Ivanhoe Mines, Johannesburg, South Africa
ABSTRACT: The supergiant Kamoa-Kakula copper deposit is a greenfields discovery
made by Ivanhoe Mines in the Western Forelands area of the Central African Copperbelt in
the Democratic Republic of the Congo. Over ten years, progressive collection of significant
geological data and completion of nearly 1500 drillholes has led to an evolving modelling
methodology to include greater geological control, meet the needs of advancing mining studies, and to solve the difficulties posed by stratigraphic and mineralisation units extensive over
many kilometres but some only a few metres to tens of metres thick. Innovative modelling
routines, combining Datamine and Leapfrog functionality, has led to a full three dimensional
(3D) model honuouring vertical grade profiles, known controls on mineralisation, and accurately representing the geometry and relationships of numerous stratigraphic and mineralised
units. Information now captured in the model has aided mining and metallurgical optimisation, which has added significant value to the project economics.
1 INTRODUCTION
The Kamoa-Kakula copper deposit is a greenfields discovery made by Ivanhoe Mines in
the Western Forelands area of the Central African Copperbelt (CACB) in the Democratic
Republic of the Congo (DRC), discovered in an area previously considered unprospective for
large copper deposits just 25 km west of the Kolwezi Cu-Co district. Ten years later, nearly
1500 drillholes have defined the largest copper deposit ever discovered in Africa, extending
28 km north-south and 23 km west-east, and with characteristics similar to the Kupfeschiefer
copper deposits in Poland. At a 1% cut-off, the deposit boasts an Indicated Resource of
1387 Mt at 2.64% Cu and an Inferred Resource of 316 Mt at 1.76% Cu. Mine development
has commenced and the project has attracted international investment.
Since its discovery, mapping, geophysical surveys and a growing drillhole database have
allowed for significant advancements in the geological understanding of the deposit, in particular the controls on mineralisation. Traditionally, understanding geological processes is a
key focus during the exploration phase, but emphasis tends to shift to ensuring the geometry
is correct once resource estimation and mine planning commence. In the modelling approach
developed at Kamoa-Kakula, both the geological processes controlling mineralisation and
accuracy in geometry are combined to produce a high quality resource model. This is achieved
without making the model so complex that it is impractical to update on a regular basis.
2 GEOLOGY
2.1 Regional geology
The CACB is the world’s premier sediment-hosted copper province. It is contained in the
Katangan basin, an intracratonic rift that records onset of growth at ∼840 Ma and inversion at