XML 141 R84.htm IDEA: XBRL DOCUMENT v3.23.1
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, 2022
$ / oz
Apr. 30, 2007
$ / oz
Jun. 30, 2020
$ / oz
Dec. 31, 2022
$ / T
$ / oz
$ / lb
Dec. 31, 2021
$ / oz
$ / T
$ / lb
Disclosure of detailed information about property, plant and equipment [line items]          
Silver price ($/oz) 11.66 3.83 2.00    
Value Beyond Proven and Probable, Fair Value Price Per Dollar | $ / lb       361,352 330,848
Value beyond proven and probable, fair value per ounce       224 251
GREECE | Bottom of range | Individual assets or cash-generating units          
Disclosure of detailed information about property, plant and equipment [line items]          
Gold price ($/oz)       1,725 1,800
Silver price ($/oz)       22 24
Lead price ($/t) | $ / T       2,050 2,150
Zinc price ($/t) | $ / T       3,000 2,825
Discount rate       7.00% 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 ($/oz)       1,600 1,550
Silver price ($/oz)       21 21
Lead price ($/t) | $ / T       2,000 2,050
Zinc price ($/t) | $ / T       2,550 2,500
Discount rate       7.50% 6.50%