XML 150 R94.htm IDEA: XBRL DOCUMENT v3.22.1
Property, plant and equipment - Summary of key assumptions used for assessing recoverable amount of company's CGUs versus carrying values (Detail)
 1 Months Ended 3 Months Ended 12 Months Ended
Apr. 01, 2021
$ / oz
Apr. 30, 2007
$ / oz
Jun. 30, 2020
$ / oz
Dec. 31, 2021
$ / oz
$ / T
Dec. 31, 2020
$ / T
$ / oz
Disclosure of detailed information about property, plant and equipment [line items]          
Silver price ($/oz) 11.54 3.83 2.00    
GREECE | Bottom of range | Individual assets or cash-generating units          
Disclosure of detailed information about property, plant and equipment [line items]          
Gold price ($/oz)       1,800 1,850
Silver price ($/oz)       24 25
Lead price ($/t) | $ / T       2,150 2,000
Zinc price ($/t) | $ / T       2,825 2,575
Discount rate       6.00% 6.00%
GREECE | Top of range | Individual assets or cash-generating units          
Disclosure of detailed information about property, plant and equipment [line items]          
Gold price ($/oz)       1,550 1,550
Silver price ($/oz)       21 21
Lead price ($/t) | $ / T       2,050 1,975
Zinc price ($/t) | $ / T       2,500 2,400
Discount rate       6.50% 6.50%