The Karowe Mine is based on the AK6 kimberlite pipe, which is part of the Orapa Kimberlite Field (“OKF”) in Botswana. The bedrock of the region is covered by a thin veneer of wind-blown Kalahari sand and exposure is very poor. Rocks close to surface are often extensively calcretised and silcretised due to prolonged exposure on a late Tertiary erosion surface (the African Surface) which approximates to the present day land surface.

The OKF includes at least 83 kimberlite bodies, varying in size from insignificant dykes to the 110 ha AK1 kimberlite which is Debswana’s Orapa Mine. All kimberlite intrusions are of post-Karoo age. Of the 83 known kimberlite bodies, five (AK1, BK9, DK1, DK2 and AK6 which is the Karowe Mine) have been or are currently being mined, and a further four (BK1, BK11, BK12 and BK15) are recognized as potentially economic deposits.

The country rock at the Karowe Mine is sub-outcropping flood basalt of the Stormberg Lava Group (approximately 130 m thick on the Karowe property) which is underlain by a condensed sequence of Upper Carboniferous to Triassic sedimentary rocks of the Karoo Supergroup (approximately 245 m thick on the Karowe property). The Karoo sequence overlies granitic basement.

AK6 is a roughly north-south elongate kimberlite body with a near surface expression of ~3.3 ha and a maximum area of approximately 7 ha at ~120 m below surface. The body comprises three geologically distinct, coalescing pipes that taper ........

The Karowe Mine is an existing open pit mine located in Central Botswana that has been in production since 2012 and has extracted approximately 20 Mt of ore to date. Conventional open pit drill and blast mining with diesel excavators and trucks provide an average annual 2.6 Mt of kimberlite feed to the mill, plus additional ore to surface stockpiles.

The open pit mine operation is expected to terminate mid-2025 at an elevation of approximately 710 masl. The mine currently has approximately two years of stockpiled reserves, which will be increased through the life of the open pit and then consumed according to value through the end of the mine life.

All open pit mining operations are performed by mine contractors working year-round on two 12-hour shifts. The on-site mining contractor is currently performing load and haul operations with a Caterpillar 6015 Hydraulic Shovel and Caterpillar 777E/G Haul Truck pairing. The mining contract has a mixed fleet of additional production, support, and ancillary equipment available on-site.

Production rates will decrease until the end of the mine life, as no further pushbacks are planned, and the strip ratio will be reduced at depth.

There are substantial resources remaining below the economic extents of the open pit that may be extracted by underground mining methods.

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The Karowe processing plant was designed by DRA Mineral Projects for operations beginning in 2012. It consisted of a diamond milling, Dense Media Separation (DMS) and recovery plant, and associated crushing, screening and thickening systems. It was designed to process 2.5 Mt of run-of-mine (ROM) material per year with a single 200 t/h DMS module. The concentrate material from the DMS was subsequently treated through a 2.5 t/h wet x-ray recovery system for material reduction and diamond winning. This circuit was designed with adequate space to accommodate future expansions.

The Karowe plant was upgraded in 2015 with the inclusion of XRT machines installed ahead of the DMS in order to recover large diamonds. This upgrade included the construction and commissioning of a new secondary (gyratory) crusher, XRT sizing and XRT diamond recovery circuits.

In 2017, the Mega Diamond Recovery Project was completed – which included adding XRT sorting technology ahead of the A ........