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Goodwill | 12 Months Ended
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Dec. 31, 2018
Goodwill [Abstract] |
Goodwill | 12 Goodwill
|  | 2018 |  |  | 2017 |
| US$m |  | US$m |
Net book value |  |  |  |  |  |
At 1 January |  | 1,037 |  |  | 951 |
Adjustment on currency translation |  | (125 | ) |  | 86 |
At 31 December |  | 912 |  |  | 1,037 |
– cost |  | 15,861 |  |  | 17,942 |
– accumulated impairment |  | (14,949 | ) |  | (16,905 | )
At 1 January |  |  |  |  |  |
– cost |  | 17,942 |  |  | 17,144 |
– accumulated impairment |  | (16,905 | ) |  | (16,193 | )
At 31 December, goodwill has been allocated as follows: |  |  |  |  |  |
|  | 2018 |  |  | 2017 |
| US$m |  | US$m |
Net book value |  |  |  |  |  |
Richards Bay Minerals |  | 474 |  |  | 552 |
Pilbara |  | 351 |  |  | 389 |
Dampier Salt |  | 87 |  |  | 96 |
|  | 912 |  |  | 1,037 |
Impairment tests for goodwill Richards Bay Minerals Richards Bay Minerals’ annual impairment review resulted in no impairment charge for 2018 (2017: no impairment charge). The recoverable amount has been assessed by reference to FVLCD, in line with the policy set out in note 1(i) and classified as level 3 under the fair value hierarchy. FVLCD was determined by estimating cash flows until the end of the life-of-mine plan including anticipated expansions. In arriving at FVLCD, a post-tax discount rate of 8.8% (2017: 8.7%) has been applied to the post-tax cash flows expressed in real terms. The key assumptions to which the calculation of FVLCD for Richards Bay Minerals is most sensitive and the corresponding decrease in FVLCD are set out below:
| US$m
5% decrease in the titanium slag price | 174
1% increase in the discount rate applied to post-tax cash flows | 195
10% strengthening of the South African rand | 328
Other assumptions include the long-term pig iron and zircon prices and operating costs. Future selling prices and operating costs have been estimated in line with the policy set out in note 1(i). The recoverable amount of the CGU exceeds the carrying value when each of these sensitivities are applied whilst keeping all other assumptions constant. Pilbara The annual impairment review of the Pilbara CGU has been assessed by reference to FVLCD using discounted cash flows, which is in line with the policy set out in note 1(i) and is classified as level 3 under the fair value hierarchy. In arriving at FVLCD, a post-tax discount rate of 6.8% (2017: 6.7%) has been applied to the post-tax cash flows expressed in real terms. The recoverable amount was determined to be significantly in excess of carrying value, and there are no reasonably possible changes in key assumptions that would cause the remaining goodwill to be impaired.

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- Definition The disclosure of goodwill. [Refer: Goodwill] + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name IAS -Number 1 -IssueDate 2017-01-01 -Paragraph 10 -Subparagraph e -URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_10_e&doctype=Standard -URIDate 2017-03-09 + Details
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- Definition Goodwill. + References No definition available. + Details
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