Plant and equipment assets are depreciated using the straight-line method based on estimated useful lives, which generally range from 1 to 5 years. Land is not depreciated.
Where an item of plant and equipment is comprised of major components with different useful lives, the components are accounted for as separate items of plant and equipment. Expenditures incurred to replace a component of an item of property, plant and equipment that is accounted for separately, including major inspection and overhaul expenditures, are capitalized. Directly attributable expenses incurred for major capital projects and site preparation are capitalized until the asset is brought to a working condition for its intended use.
These costs include dismantling and site restoration costs to the extent these are recognized as a provision.
The cost of self-constructed assets includes the cost of materials, direct labour and an appropriate portion of normal overheads.
The costs of day-to-day servicing are recognized in profit or loss as incurred. These costs are more commonly referred to as "maintenance and repairs."
Financing costs directly associated with the construction or acquisition of qualifying assets are capitalized at interest rates relating to loans specifically raised for that purpose, or at the average borrowing rate where the general pool of group borrowings is utilized. Capitalization of borrowing costs ceases when the asset is substantially complete.
The depreciation method, useful life and residual values are assessed annually.
Leased assets
Leases in which the Company assumes substantially all risks and rewards of ownership are classified as finance leases. Finance leases are recognized at the lower of the fair value and the present value of the minimum lease payments at inception of the lease, less accumulated depreciation and impairment losses.
Subsequent costs
The cost of replacing part of an item within property, plant and equipment is recognized when the cost is incurred if it is probable that the future economic benefits will flow to the Company and the cost of the item can be measured reliably. All other costs are recognized as an expense as incurred.
Impairment
The Company's tangible assets are reviewed for an indication of impairment at each statement of financial position date. If indication of impairment exists, the asset's recoverable amount is estimated.
An impairment loss is recognized when the carrying amount of an asset, or its cash-generating unit, exceeds its recoverable amount. A cash-generating unit is the smallest identifiable group of assets that generates cash inflows that are largely independent of the cash inflows from other assets or groups of assets. Impairment losses are recognized in profit and loss for the period.
Impairment losses recognized in respect of cash-generating units are allocated first to reduce the carrying amount of any goodwill allocated to cash-generating units and then to reduce the carrying amount of the other assets in the unit on a pro-rata basis.
The recoverable amount is the greater of the asset's fair value less costs to sell and value in use. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax discount rate that reflects current market assessments of the time value of money and the risks specific to the asset. For an asset that does not generate largely independent cash inflows, the recoverable amount is determined for the cashgenerating unit to which the asset belongs.
Reversal of impairment
An impairment loss is reversed if there is an indication that there has been a change in the estimates used to determine the recoverable amount. An impairment loss is reversed only to the extent that the asset's carrying amount does not exceed the carrying amount that would have been determined, net of depreciation or amortization, if no impairment loss had been recognized. An impairment loss with respect to goodwill is never reversed.