Lesotho

Mothae Mine

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Overview

Mine TypeOpen Pit
StatusActive
Commodities
  • Diamond
Mining Method
  • Truck & Shovel / Loader
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Snapshot2022 was a challenging for the Mothae operations, some mass balance bottlenecks were encountered in the plant following the plant upgrades in 2021, leading to a lower than designed increase to plant throughput.

Recoveries included 197 Special sized stones and 651 diamonds greater than 4.8 carats.

Owners

SourceSource
CompanyInterestOwnership
Government of the Kingdom of Lesotho 30 % Indirect
Lucapa Diamond Company Ltd. 70 % Indirect
Mothae Diamonds (Pty) Ltd. (operator) 100 % Direct
Lucapa Diamond Company Limited holds a 70% interest in Mothae Diamonds (Pty) Limited which has a 100% interest in the Mothae Diamond Project. The remaining 30% of Mothae Diamonds is held by the Government of Lesotho.

Deposit type

  • Kimberlite

Summary:

The Mothae kimberlite intrusion is a kimberlite diatreme, or pipe, which was the feeder to a now eroded kimberlite volcano.

The Mothae kimberlite is situated on the southern edge of the Kaapvaal Craton, which extends through central, eastern and north-eastern South Africa, into southern Zimbabwe and southeastern Botswana, and incorporates most of Swaziland.

As the diamondiferous Northern Lesotho Kimberlite Field is in the Kaapvaal Craton, it conforms to ‘Clifford’s Rule’, which states that diamondiferous kimberlites tend to occur in geological regions that have been tectonically stable since the Archaean.

The Archaean basement in Lesotho is entirely covered by the flat-lying Paleozoic to Mesozoic Karoo Supergroup which reaches a thickness of approximately 4 km in Lesotho.

The surface geology within the Mothae license area comprises amygdaloidal and nonamygdaloidal Mesozoic (180 Ma) Drakensberg Group flood basalt, into which the Mothae kimberlite has intruded. The average elevation of the Mothae kimberlite is approximately 2,900 mamsl and the thickness of the basalt into which it is emplaced is estimated to be of the order of 1,000 m, although basalt thickness on the property may locally reach up to 1,400 m. Basalts are underlain by Beaufort Group sediments of the Karoo Supergroup.

Kimberlite emplacement during the Cretaceous Period was widespread throughout southern Africa and was probably associated with tectonic triggers during the break-up of Gondwana (Bailey, 1992).

The Mothae kimberlite consists of a main southern pipe-like lobe (South Lobe) connected to a smaller northern lobe (North Lobe) by an elongate central kimberlite body (Neck). The South Lobe has a surface expression of 5.05 ha and the three areas combined form a total surface area of 8.81 ha. Wall rock contacts for the North and South Lobes have been delineated by geophysical data, mapping and drill core intercepts. The contact between the kimberlite and the basalt is typically sharp and steep with localised zones of wall rock breccia.

The kimberlite itself comprises almost entirely of massive volcaniclastic kimberlite (“VK”) of different types. The different kimberlite types have been ‘fingerprinted’ in terms of their Kimberlite Indicator Mineral (“KIM”) content and petrographic characteristics as a control on bulk sampling; this being important as each has a different diamond grade and revenue.

Reserves

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Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

2020 was a disjointed year for Mothae as a consequence of the COVID-19 pandemic, with the mining operations being suspended from the end of March 2020 to the beginning of October 2020.
CommodityUnits20232022202120202019
Diamond carats  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe30,107
All production numbers are expressed as mineral. ^ Guidance / Forecast.

Operational metrics

Metrics20232022202120202019
Tonnes processed  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1,156,093 t
Annual processing capacity  ....  Subscribe  ....  Subscribe  ....  Subscribe  ....  Subscribe1.1 Mt
^ Guidance / Forecast.

Production Costs

CommodityUnits20222021
Cash costs (sold) Diamond USD  ....  Subscribe
Total cash costs Diamond USD  ....  Subscribe

Operating Costs

Currency20222021
Total operating costs ($/t milled) USD 19.3  15.3  

Financials

Units2022202120202019
Revenue M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 16.5  
EBITDA M USD  ....  Subscribe  ....  Subscribe  ....  Subscribe 1.2  

Heavy Mobile Equipment

Fleet data has not been reported.

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Sep 13, 2023
....................... Subscription required ....................... Subscription required Subscription required Sep 13, 2023
....................... Subscription required ....................... Subscription required Subscription required Sep 13, 2023
....................... Subscription required ....................... Subscription required Subscription required Sep 13, 2023

EmployeesContractorsTotal WorkforceYear
...... Subscription required 2022
...... Subscription required ...... Subscription required ...... Subscription required 2021

Aerial view:

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