The Karowe Mine is exploiting the AK6 kimberlite which is part of the Orapa Kimberlite Field (OKF) in the Central District of Botswana. The OKF includes at least 83 kimberlite bodies of post-Karoo age. Three of these (AK1, BK9, and AK6) have been, or are currently being mined and four (BK1, BK11, BK12 and BK15) are recognized as potentially economic deposits. The Karowe Mine is one of the world’s most significant producers of large and high-value diamonds including Type IIa and coloured diamonds.

The OKF lies on the northern edge of the Central Kalahari Karoo Basin along which the Karoo succession dips very gently to the south-southwest and off-laps against Precambrian rocks that occur at shallow depth within the Makgadikgadi Depression. The country rock at Karowe is sub-outcropping flood basalt of the Stormberg Lava Group (~130 m thick), underlain by a condensed sequence of Upper Carboniferous to Triassic sedimentary rocks of the Karoo Supergroup (~345 m thick), below which is the granitic basement

AK6 is a roughly north-south trending elongate kimberlite body with a surface expression of ~3.3 ha and maximum area of ~8 ha at approximately 120 m below surface. It comprises three geologically distinct, coalescing pipes known as the North, Centre and South Lobes that taper with depth into discrete roots. The kimberlite in each lobe is different, in terms of its textural characteristics, relative proportion of internal country rock dilution, degree of weat ........

The Karowe Mine is an existing open pit operation, which has been in production since 2012. 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. All open pit mining activities are performed by Botswanan mine contractors working 365 days per year on three, eight-hour shifts in the pit and two, 12-hour shifts in the processing facility. The open pit mine operation is expected to terminate mid-2025, ending at an elevation of approximately 700 masl.

There are substantial resources remaining below the economic extents of the open pit that may be extracted by underground mine methods. A 7,200 t/d shaft operation utilizing long hole shrinkage mining (a form of fully-assisted caving) is proposed to provide an additional 13 years of mine life to the Karowe operation after a five-year construction period commencing in 2020.

The Karowe resource contains three distinct coalescing pipes, referred to as the North, Centre, and South Lobe. All lobes are outcropping, dip vertically, and vary in diameter and depth. The South Lobe is the largest of the three, and its Indicated Resources extend approximately 760 mbs (from 1,010 masl to 250 masl). The North and Centre Lobes extend below the open pit limit but have been excluded from the planned underground mine as they are inferred at depth and are of low value.

The long hole shrinkage method (LHS) is planned to systematic ........

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