There is information on their depreciation accounting in the...

There is information on their depreciation accounting in the annual report page 73 for example:

"Each class of plant and equipment is carried at cost or fair value as indicated less, where applicable, any accumulated depreciation and impairment losses.
Properties are shown at fair value based on valuations by external independent valuers, less subsequent depreciation for buildings. Any accumulated depreciation at the date of revaluation is eliminated against the carrying amount of the asset and the net amount is restated to the revalued amount of the asset. All other plant and equipment are stated at historical cost less depreciation. Historical cost includes expenditure that is directly attributable to the acquisition of the items.
The net carrying amount of property, plant and equipment is reviewed for impairment in accordance with Note 1(u). "

I wonder also, usually a mine can be it's own subsidiary company, if this was the case then wouldnt all the assets just be carried as they are in the books of the subsidiary rather than the cost of purchase? I don't think it is such a big effect anyhow. Could also check the broker report posted after the purchase and see what they forecast for cash and capital costs...