2.

Significant accounting judgements and estimates
   
2.1 Judgements
  In applying the group’s accounting policies, management has made the following judgements, including those involving estimations, which could have a significant effect on the amounts recognised in the financial statements:

Consolidation of special-purpose vehicles
The Boleng Trust and Fricker Road Trust (the trusts) are broad-based community trusts which are for the benefit of historically disadvantaged South Africans (HDSAs) as contemplated in the Mining Charter. The trusts are invested in special-purpose vehicles (SPVs), namely Main Street 350 Proprietary Limited (RF), Main Street 460 Proprietary Limited (RF) and Main Street 904 Proprietary Limited (RF). The group has considered the requirements of IFRS 10 in assessing whether or not it controls the trusts and the SPVs both which are considered to be structured entities (SEs) as defined in IFRS 10. Based on the contractual terms (namely those contained in the relationship agreements which govern the operation of SEs) the voting rights in the SEs are not considered to be the dominant factor in determining control. Factors such as design and purpose of the SEs, the fact that the SEs are indebted to the group, together with the restrictions placed on the Assore shares held by the SEs (either directly or indirectly) have resulted in the group’s management concluding that the SEs (the trusts and the SPVs) are controlled by the group and have therefore been consolidated in the group financial statements in order to comply with the requirements of IFRS 10. Similarly, since the Assore Employee Trust (also an SE), which is operated by the group and the SPV in which the trust is invested, is indebted to the group, has been consolidated in the group financial statements in accordance with IFRS 10. Accordingly, the Assore shares controlled by these SEs are accounted for as treasury shares (refer item 14).

Impairment of available-for-sale investments
The group records impairment charges on available-for-sale equity investments when there has been a significant or prolonged decline in fair value below their original cost. The determination of what is significant or prolonged requires judgement. In making this judgement, the group evaluates, among other factors, historical share price movements and the duration and extent to which the fair value of an investment is less than its original cost.

Refer note 4 for the impairment on the available-for-sale investments.
   
2.2 Estimation uncertainty
  The key assumptions concerning the future and other key sources of estimation uncertainty at the statement of financial position date that have a significant risk of causing a material adjustment to the carrying amounts of assets and liabilities within the next financial year are listed below.

Project risk and exploration expenditure
In evaluating whether expenditures meet the criteria to be capitalised, the group utilises several different sources of information, including:
  • the degree of certainty over the mineralisation of the orebody;
  • commercial risks including, but not limited to, country risks; and
  • prior exploration knowledge available about the target orebody, which reduces the level of risk associated with the capitalisation of this expenditure to an acceptable level.
Production stripping costs
The group incurs waste removal costs (stripping costs) during the development and production phases of its surface mining operations. Furthermore, during the production phase, stripping costs are incurred in the production of inventory as well as in the creation of future benefits by improving access and mining flexibility in respect of the orebodies to be mined, the latter being referred to as a stripping activity asset. Judgement is required to distinguish between the development and production activities at the surface mining operations.

The group is required to identify the separately identifiable components of the orebodies for each of its surface mining operations. Judgement is required to identify and define these components, and also to determine the expected volumes (tonnes) of waste to be stripped and ore to be mined in each of these components. These assessments may vary between mines because the assessments are undertaken for each individual mine and are based on a combination of information available in the mine plans, specific characteristics of the orebody, the milestones relating to major capital investment decisions and the type and grade of minerals being mined.

Judgement is also required to identify a suitable production measure that can be applied in the calculation and allocation of production stripping costs between inventory and the stripping activity asset. The group considers the ratio of expected volume of waste to be stripped for an expected volume of ore to be mined for a specific component of the orebody, compared to the current period ratio of actual volume of waste to the volume of ore to be the most suitable measure of production.

These judgements and estimates are used to calculate and allocate the production stripping costs to inventory and/or the stripping activity asset(s). Furthermore, judgements and estimates are also used to apply the units of production method in determining the depreciable lives of the stripping activity asset(s). Refer note 2 in the notes to the consolidated financial statements.

Provisions for environmental rehabilitation
The group provides for the estimated costs of rehabilitation which include both restoration and decommissioning of associated assets. An environmental liability assessment is conducted by an independent adviser on an annual basis to assess the adequacy of the environmental rehabilitation provisions. A risk of material adjustment exists due to the inherent uncertainty surrounding the future life of the mines, the forward-looking nature of the provisions and the uncertainty regarding the underlying assumptions. Refer note 14 in the notes to the consolidated financial statements.

Ore Reserve and Resource estimates
Ore Reserves are estimates of the amount of ore that can be economically and legally extracted from the group’s mines, based on Proven and Probable Ore Reserves. The group estimates its Ore Reserves and Mineral Resources based on information compiled by appropriately qualified persons, relating to the geological data on the size, depth and shape of the orebody, and require complex geological judgements to interpret the data. Changes in the Reserve or Resource estimates may impact the carrying value of exploration and mining assets in terms of depreciation charged and possible impairment. Refer note 2 in the notes to the consolidated financial statements.

Depreciation based on units of production
Costs related to the development and infrastructure of the mine to the stage when economically accessible reserves are to be extracted, are depreciated over the entire Proven and Probable Reserves for the relevant Mineral Resource. Subsequent development and infrastructure costs incurred in accessing Mineral Resources are depreciated over the expected Proven and Probable Reserves expected to be extracted for each phase of the planned mining activity, taking into account reasonably certain plans for ongoing economically feasible mining activity. Refer note 2 in the notes to the consolidated financial statements.

Impairment of non-financial assets
The group assesses each cash-generating unit annually to determine whether any indications of impairment exist. Where an indicator of impairment exists, a formal estimate of the recoverable amount is made, which is considered the higher of the fair value less cost to sell and value-in-use. These assessments require the use of estimates and assumptions such as commodity prices, discount rates, future capital requirements, exploration potential and operating performance. Fair value is determined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value for mineral assets is generally determined as the present value of estimated future cash flows arising from the continued use of the asset, which includes estimates such as the cost of future expansion plans and eventual disposal, using assumptions that an independent market participant may take into account. Cash flows are discounted at an appropriate discount rate to determine the net present value. For the purpose of calculating the impairment of any asset, management regards an individual mine or works site as a cash-generating unit. (Refer note 2 in the notes to the consolidated financial statements.)