Prospectivity
cu-v3.0
Sediment-hosted copper, Kalahari Copperbelt
All runs Does not rank
This run does not rank ground
- The blind-site hit rate is 50% against a threshold of 70%.
- The competent person rejected this run.
Nothing below is presented as a ranked target. The record stays visible so the next run can be built from what this one found.
Mineral system
Cu Copper Definition 2.0
Sediment-hosted copper, Kalahari Copperbelt
Signed by T. Kgosi, Pr.Sci.Nat on 02 Jul 2026
Random forest, redox-constrained · 500 m
Ran 21 Jul 2026, 108 min
Run by: Amini modelling team · Accepted by: T. Kgosi, Pr.Sci.Nat
Superseded by cu-v3.1Capture efficiency
The top 10% of ranked ground holds 55% of the known deposits.
Search-space reduction 92.3%
The share of the modelled area a competent person can set aside for this commodity.
Validation
Blind-site hit rate 50%
Threshold agreed at MS1 70%
Block cross-validation 5 folds, 40 km blocks
AUC 0.79 ± 0.09
Physical constraints
- Prediction is confined to the D'Kar / Ngwako Pan redox contact and its permissible stratigraphy.
Features and importance
| Feature | Critical process | System role | Importance |
|---|---|---|---|
| Distance to interpreted redox contact | Trap: reduced host against oxidised red-bed source rock | Trap | |
| Cu-Ag-Co pathfinder residual | Source and transport: leakage of metal-bearing brine to surface | Transport | |
| Magnetic low, graben margin | Transport: basin-margin faults route brine to the contact | Transport | |
| Kalahari cover thickness | Preservation and detectability: cover attenuates every surface proxy | Preservation |
Inputs
| Dataset | Version | Confidence filter | Coverage |
|---|---|---|---|
| Ghanzi aeromagnetics | 2004 levelled | A and B only | 94% |
| Geology 1:250k with Pre-Kalahari interpretation | 2023 | all, lineage recorded | 100% |
| KCB regional soil geochemistry | 2019 | C or better | 38% |
KCB regional soil geochemistry covers 38% of the modelled area and is the layer that governs the bounds.
Validation
| Withheld site | Withheld by | Class | In the high class |
|---|---|---|---|
| BS-CU-01 Zone 5 extension | T. Kgosi, Pr.Sci.Nat | High | In the high class |
| BS-CU-02 Boseto west | T. Kgosi, Pr.Sci.Nat | High | In the high class |
| BS-CU-03 Ghanzi ridge south | T. Kgosi, Pr.Sci.Nat | Low | Missed |
| BS-CU-04 Mahumo | T. Kgosi, Pr.Sci.Nat | Medium | Missed |
| BS-CU-05 Plutus | T. Kgosi, Pr.Sci.Nat | High | In the high class |
| BS-CU-06 Banana Zone north | T. Kgosi, Pr.Sci.Nat | Medium | Missed |
Outputs
- Prospectivity surface 3.0 · COG, 500 m
- Confidence surface 3.0 · COG, 500 m
Parameters
- trees
- 500
- maxDepth
- unlimited
- classCut
- high ≥ 0.80, medium ≥ 0.55
- negatives
- 2:1, random outside known occurrences
Limitations and completeness
- Blind-site hit rate of 50% against a threshold of 70%: this edition never ranked ground.
- 500 m grid: too coarse to separate targets inside a single graben.
- Negatives drawn at random, which flatters the reported separation.
Against the previous edition
This is the first edition of this model.
Targets from this run
0 targets are attributed to this run and are held back from ranking.