| 2.8) | PROPERTY, MACHINERY AND EQUIPMENT (note 14) |
Property, machinery and equipment are recognized at their acquisition or construction cost, as applicable, less accumulated depreciation and accumulated impairment losses. Depreciation of fixed assets is recognized as part of cost and operating expenses (note 5), and is calculated using the straight-line method over the estimated useful lives of the assets, except for mineral reserves, which are depleted using the units-of-production method. As of December 31, 2017, the average useful lives by category of fixed assets were as follows:
| Years | ||||
|
Administrative buildings |
35 | |||
|
Industrial buildings |
30 | |||
|
Machinery and equipment in plant |
17 | |||
|
Ready-mix trucks and motor vehicles |
9 | |||
|
Office equipment and other assets |
6 | |||
CEMEX capitalizes, as part of the related cost of fixed assets, interest expense from existing debt during the construction or installation period of significant fixed assets, considering CEMEX’s corporate average interest rate and the average balance of investments in process for the period.
All waste removal costs or stripping costs incurred in the operative phase of a surface mine in order to access the mineral reserves are recognized as part of the carrying amount of the related quarries. The capitalized amounts are further amortized over the expected useful life of exposed ore body based on the units of production method.
Costs incurred in respect of operating fixed assets that result in future economic benefits, such as an extension in their useful lives, an increase in their production capacity or in safety, as well as those costs incurred to mitigate or prevent environmental damage, are capitalized as part of the carrying amount of the related assets. The capitalized costs are depreciated over the remaining useful lives of such fixed assets. Periodic maintenance on fixed assets is expensed as incurred. Advances to suppliers of fixed assets are presented as part of other long-term accounts receivable.
The useful lives and residual values of property, machinery and equipment are reviewed at each reporting date and adjusted if appropriate.