10. Property, plant and equipment
 
   Freehold land 
and buildings 
US$’000 		 Mining 
assets and 
infrastructure 
US$’000 		 Mining 
fleet 
US$’000 		 Right-of-use 
asset: 
mining fleet 
US$’000 		 Motor 
vehicles 
US$’000 		 Computer 
equipment 
and software 
US$’000 		 Office 
equipment 
and furniture, 
community 
and site office 
improvements 
US$’000 		 Right-of-use 
asset: 
buildings 
US$’000 		 Leasehold 
improvements 
US$’000 		 Total 
US$’000 		   
30 September 2018                                  
Cost                                  
Balance at 30 September 2017  15 354  266 019  7 030  –  594  5 542  796  –  220  295 555    
Adoption of IFRS 16 (refer note 3) –  –  –  –  –  –  –  1 503  (220) 1 283    
Balance at 1 October 2017  15 354  266 019  7 030  –  594  5 542  796  1 503  –  296 838    
Additions  150  21 429  16 473  6 910  88  2 167  147  791  –  48 155    
Business combination (note 21) –  1 886  21 466  6 527  –  –  –  –  –  29 879    
Transfers  –  –  (2 203) 2 203  –  (15) (114) 129  –  –    
Disposals  –  –  (145) –  –  (97) (29) –  –  (271)   
Assets written off  –  (266) (2 539) (159) –  (1) –  –  –  (2 965)   
Exchange differences on translation  (643) (12 723) (3 210) (1 299) (31) (373) (29) (127) –  (18 435)   
Balance at 30 September 2018  14 861  276 345  36 872  14 182  651  7 223  771  2 296  –  353 201    
Accumulated depreciation                                  
Balance at 30 September 2017  592  59 337  299   –    289    1 914    518   –    47    62 996    
Adoption of IFRS 16  –  –  –  –  –  –  –  164  (47) 117    
Balance at 1 October 2017  592  59 337  299  –  289  1 914  518  164  –  63 113    
Charge for the year  188  16 761  7 700  2 963  69  1 712  93  372  –  29 858    
Transfers  –  –  (80) 80  –  (6) (23) 29  –  –    
Disposals  –  –  –  –  –  (87) (28) –  –  (115)   
Impairment/assets written off  –  –  1 020  (88) –  –  –  –  –  932    
Exchange differences on translation  (40) (3 708) (665) (223) (17) (193) (19) (33) –  (4 898)   
Balance at 30 September 2018  740  72 390  8 274  2 732  341  3 340  541  532  –  88 890    
   Freehold 
land and 
buildings 
US$’000 		 Mining 
assets 
and 
infrastructure 
US$’000 		 Mining 
fleet 
US$’000 		 Leasehold 
improve- 
ments 
US$’000 		 Computer 
equip- 
ment 
and 
software 
US$’000 		 Motor 
vehicles 
US$’000 		 Office 
equipment 
and 
furniture, 
community 
and site 
office 
improvements 
US$’000 		 Total 
US$’000 		   
Balance 30 September 2016                            
Opening balance  14 504  248 588  –  130  2 077  515  554  266 368    
Additions  666  14 602  7 124  189  3 504  73  240  26 398    
Disposals  –  (231) –  (99) (19) –  –  (349)   
Exchange differences  184  3 060  (94) –  (20) 6  2  3 138    
Balance at 30 September 2017    15 354    266 019    7 030    220    5 542    594    796    295 555    
Accumulated depreciation                            
Balance at 30 September 2016    414    43 429  –  –    127    1 203    198    463    45 834    
Charge for the year  174  15 570  303  16  725  90  51  16 929    
Disposals  –  (35) –  (99) (19) –  –  (153)   
Exchange differences  4  373  (4) 3  5  1  4  386    
Balance at 30 September 2017    592    59 337    299    47    1 914    289    518    62 996    
  30 September
2018
US$’000		   30 September
2017
US$’000		  
Net book value        
Freehold land and buildings 14 121   14 762  
Mining assets and infrastructure 203 955   206 682  
Mining fleet 28 598   6 731  
Right-of-use mining fleet 11 450   –  
Motor vehicles 310   305  
Computer equipment and software 3 883   3 628  
Office equipment and furniture, community and site office improvements 230   278  
Right-of-use buildings and premises 1 764   –  
Leasehold improvements –   173  
  264 311   232 559  

Included in additions to mining assets and infrastructure are additions to the deferred stripping asset of US$1.3 million (2017: no additions).

The estimated economically recoverable proved and probable mineral reserve was reassessed at 1 October 2017 which gave rise to a change in accounting estimate. The remaining reserve that management had previously assessed was 100.3 Mt (at 30 September 2016) and at 30 September 2017 was assessed to be 97.0 Mt.

As a result, and taking into account depletion of the reserve during the year ended 30 September 2017 (5.0 Mt), the expected useful life of the plant increased. The impact of the change on the actual depreciation expense, included in cost of sales, is a reduced depreciation charge of US$0.2 million.

Included in mining assets and infrastructure are projects under construction of US$20.5 million (2017: US$9.0 million).

Freehold land and buildings comprises various portions of the farms Elandsdrift 467 JQ, Buffelspoort 343 JQ and 342 JQ, North West province, South Africa. All land is freehold.

Property, plant and equipment, with the exception of motor vehicles, is insured at approximate cost of replacement. Motor vehicles are insured at market value. Land is not insured.

Capital commitments

At 30 September 2018, the Group’s capital commitments for contracts to purchase property, plant and equipment amounted to US$6.0 million (2017: US$6.5 million).

Securities

At 30 September 2018, US$11.4 million of the carrying amount of the Group’s mining fleet was pledged as security against the equipment loan facility. At 30 September 2017, US$213.5 million was secured against the secured bank borrowings. The secured bank borrowings was settled in full during the year ended 30 September 2018.

Assets written off/impairment

During the year ended 30 September 2018, the Group impaired and scrapped assets totalling US$3.9 million. The impairment and assets written off relate to costs capitalised to the construction of a new plant and to yellow fleet equipment identified as no longer fit for use and premature component failures. The Group decided not to proceed with the construction of the new plant.