The Argyle AK1 orebody was discovered in 1979 and subsequently found to be a large, economically viable reserve with high grade diamondiferous ore. Production began via an open pit operation at the end of 1985 and has continued for some 25 years to present day. This, however, will come to an end in the next few years with production moving to an underground operation via block-cave mining methods. A series of studies from 2001 - 2005 was carried out; diamond drilling commenced after approval in 2006, from an exploration drive to determine the likelihood of the current proposed block cave operation. In 2006, development of the block cave project began, in order to realise the part of the orebody below the extent of the open pit mining operation. Development of the block cave technique, comprising an undercut level beneath the target zone of the orebody with subsequent extraction level 15 - 20 m beneath, relies largely on a number of block-caving parameters (hydraulic radius, rock type, structure and orientation of stress and grade of the orebody). These all have an infl uence on cave ability and eventual profi t of the operation. Evaluation of further potential for taking this orebody beyond the block cave phase with options such as sublevel-caving are being considered for the UG-2 portion of the resource/reserve. Diamond drilling for this work is currently under revise. The challenges faced in transitioning form the surface operations to the underground, comprising a changing workforce, converging development drives, underground aquifers, major excavations and transportation of ore via automation are intriguing.
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