Overview
Mine planning

The main objectives of the Implats integrated planning cycle have remained as follows:

• To utilise the full available time per year for quality planning
• To allow integration of the different levels of planning
• To ensure the planning levels are done in the correct sequence
• To populate the cycle with appropriate review processes
• To link the planning cycle to business reporting periods
• To provide continuity of plans and cycles
• To place emphasis on risk and value
• To identify departmental inputs and ensure full participation
• To ensure changes in the business environment are continuously incorporated
• To ensure top-down goals flow through to operational planning and vice versa
• To ensure optimisation of plans
• To enhance compliance with standards, consolidation and delivery of results.

The planning cycle was revised during the past year to further optimise the process. Consideration was given to the sequence of planning, the duration of the business planning period and the embedding of long-term strategic planning. In particular the approach to commence the planning cycle with the updating of the life-of-mine (LoM) planning process and followed by a detailed five-year development and two-year stoping scheduling phase has been adopted. The main benefits of this approach is conducting the detailed planning phase as late as possible in the cycle to ensure proper alignment with the delivery phase of the plan and also allocating more time to the life-of-mine planning phase.

Implats has defined three levels of life-of-mine planning, these being classified as Levels III, II and I, shown adjacent, which also illustrates a broad alignment with resource and reserve categories. The three levels are linked to increasing levels of confidence and the conversion of mineral resources to mineral reserves.

LoM Level III includes “Blue Sky” and scoping studies, and therefore focuses mainly on inferred resources and exploration results. It also includes contiguous areas and opportunities outside existing lease boundaries and ownership. Clearly, valuation on these resources can only be done internally, for the purpose of justifying expenditure for the upgrading of the inferred resources.

LoM Level II includes planned but as yet unapproved projects, which have a reasonable chance of future board approval.

LoM Level I includes operational shafts and approved capital projects where a portion of mineral resources is converted to mineral reserves and sufficient confidence exists for the declaration of mineral reserves in a public report.

Estimation of grade block models is facilitated by geostatistical packages such as Isatis™ and Datamine™ and is based on a fit-for-purpose principle. Mine design and scheduling utilise 3D planning tools; the output of which supports the mineral reserve estimates. Grade and tonnage modifying factors are stored in electronic databases. The planning process involves the conversion of resources to reserves through the allocation of modifying factors to the in situ resource through detail design and scheduling. Factors used include densities per rock type and dimensions appropriate to the mining method deployed. In some cases the mineralised channel is narrower than the minimum safe mining width and so additional waste material has to be included in the mining cut. Historical dilution factors are incorporated into the plan taking into account anticipated future conditions and improvements where possible. Dilution factors used include overbreaks, underbreaks and off-reef mining. Cognisance is taken of the practicalities of hard rock mining and the limitations of the tools used. This is allocated on a half level basis which allows the varying conditions across the lease area to be recognised and integrated into the LoM plan. Where there is no history, factors from similar operations are used as a guideline. Planning parameters are informed in part by historic and anticipated future constraints, orebody permitting.

At Impala, the mine managers and general managers oversee the compilation and approve their respective shafts’ production profiles. These profiles are further endorsed by the executive: mining and the Group planning manager. In addition, graphical plans depicting the planned layouts, design and sequence of mining are interrogated and signed off by the mine manager, mine planner, geologist, surveyor, rock engineer and ventilation officer of each shaft. Minor variations of this approval protocol are used at other Group operations but work is ongoing to standardise the procedure across the Group.

High-level classification of life-of-mine plans