Summary

Mine Type	Open Pit
Status	Active
Commodities	Diamond
Mining Method	Truck & Shovel / Loader
Production Start	...
Mine Life	...
Snapshot	Over the past three decades, the Catoca mine has grown to become the world’s fourth-largest open-pit diamond mine, accounting for approximately 75% of Angola’s diamond output. Feasibility studies are under way to explore the potential for underground mining, which could ensure the continuity of production beyond that depth.

Deposit type

• Kimberlite

Summary:

Catoca is the largest of all kimberlite pipes in the Lucapa kimberlite structure in northeastern Angola, covering a surface area of about 64 hectares.

According to Ustinov et al. (2018) approximately one thousand kimberlite pipes in 36 kimberlite fields have been discovered in Angola. Approximately twenty pipes are known with grades in the range 0.1 to 0.5 ct/t, and five of six pipes with grades > 0.5 ct/t occur within the Catoca kimberlite field (namely Catoca, Tchiuzo, CatE42, Luax071 and Luax072 or Luele, Ustinov et al. 2018).

The geological model of Catoca presented by Pervov et al. (2017) is presented in simplified and generalized format below. The authors describe the Catoca kimberlite as a symmetrical upward flaring pipewith a 64 ha footprint atsurface (at 970masl. The pipe is infilled with crater zone rock types to a depth of 255-275 mbs (705±10 masl) where a sharp near-horizontal contact zone marks the transition to diatreme-zone kimberlite rock types.

The geological evolution of Catoca, arranged from oldest to youngest, comprises the following:
• Unit 1 represents massive-textured primary volcaniclastic (pyroclastic) kimberlite, a characteristic rock type of the diatreme zone thattypically contains angular brecciated.

Fragments of county-rock gneiss and schist (previously named “tuffisitic kimberlite breccia” or TKB). The pyroclastic kimberlite constitutes a well-mixed zone at the Catoca mine and is expected to have reasonably consistent diamondcontent.Multiple separate pyroclastic kimberlite units often occur in diatreme zones of large kimberlite pipes, each typically with distinct diamond grades. Diatreme-zone rock types also often represent the material extracted by underground cave mining methods, and their geotechnical properties are consequently of interest for life-of-mine planning.

• Unit 2 contains country-rock gneiss blocks set in a matrix of volcaniclastic material with lenses of water-lain sediment, implying deposition by crater-edge landslides and mudflows in a crater that was open to influx of surface runoff.

• Units 3 and 4 are banded pyroclastic and resedimented volcaniclastic kimberlite thatrepresent a mix of volcaniclastic plastering against the crater walls and the early stages of crater infill by volcanic ejecta and disturbed country rock piled up above the crater rim. Variable diamond grades are expected in these environments.

• Unit 6 comprises a volcano sedimentary sequence with a complex structure imposed by influx of extra- crater sand material in avalanches, slumps and vast mud–sand flows. Multiple intercalations occur of< 1 m scale tuffaceous sandstone, quartz-rich sandstone and rhythmic laminae of silt- to mudstone. Thick 10 m scale mudstones occur toward the upper part of Unit 6. Selective mining of Unit 6 may be possible, though most at Catoca is considered sterile waste rock.

• Unit 7 is a quartz-rich sandstone effectively devoid of kimberlitic components. It fills the uppermost part of the crater depression at Catoca to a depth of 105 m. Such crater-filling sand rich units are commonly encountered during exploration drilling of large (30 to 160 ha) Angolan kimberlites;their presence to a depth of 350 m in select Angolan kimberlites signifies preservation of a complete kimberlite crater zone and a lack of post-eruptive erosion.

• All other younger sediments at Catoca are considered to be overlying and correlated with the Calonda and Kalahari deposits.

The Catoca kimberlite pipe is a symmetrical flaring upward body of about 63.6 ha in area on the pipe surface (970 masl = metres above sea level). The contact between crater and diatreme zones is sharp and nearly horizontal (705±10 masl). The diatreme zone is composed of massive-textured pyroclastic kimberlite with coherent kimberlite as minor dikes and local diatreme infill (Unit 1). The crater zone is more complicated and consists of earlier relict ring of resedimented volcaniclastic kimberlite and banded pyroclastic kimberlite (Units 3 and 4) and later central depression of epiclastic kimberlite (Units 6 and 7). The ring is separated from the central depression by a circular zone of extensive steeply dipping dislocations with boudinage and numerous bedding-plane and stepped dip-slip faults.

The diatreme to crater transition displays abrupt changes in lithology and rock attitude. The upper diatreme Unit 2 is 4 to 44 m thick. It consists of frequent intercalation of quartz-free kimberlitic tuffs with variable particle sizes (granule, sand, silt to mud; normally graded beds are characteristic) – 80%, as well as breccias (30–60% xenoliths) and gneiss blocks – totally 20% by thickness.

Mining Methods

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Comminution

Crushers and Mills

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Processing

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Commodity Production

Commodity	Units	2024	2023	2022	2021	2020
Diamond	M carats	....	....	....	....	....

Operational metrics

Metrics	2023	2022	2021	2020
Hourly processing rate	....	....	....	....
Ore tonnes mined	....	....	....	....
Waste	....	....	....	....
Tonnes processed	....	....	....	....

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Jan 31, 2026
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Employees	Year
......	2023
......	2022
......	2021
......	2020