Significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2019

Significant accounting policies [Abstract]

Disclosure of foreign exchange rates used o translate monetary items [Text Block]

The main exchange rates and UF used to translate monetary assets and liabilities, expressed in foreign currency at the end of each period in respect to U.S. dollars, are as follows:

Currencies	As of December ‎ 31, 2019		As of December ‎ 31, 2018
	US$		US$
Brazilian real		4.02		3.87
New Peruvian sol		3.31		3.37
Argentine peso		59.83		37.74
Japanese yen		108.9		110.38
Euro		0.89		0.87
Mexican peso		18.89		19.68
Australian dollar		1.43		1.42
Pound Sterling		0.76		0.79
South African rand		14.06		14.35
Ecuadorian dollar		1.00		1.00
Chilean peso		748.74		694.77
Chinese yuan		6.98		6.88
Indian rupee		71.31		69.93
Thai Baht		29.97		32.53
Turkish lira		5.94		5.27
Polish Z l o ty		3.79		-
UF (*)		37.81		39.68

(*) US$ por UF

Disclosure of useful lives of property, plant and equipment [Text Block]

The useful lives used for the depreciation and amortization of assets included in property, plant and equipment in years are presented below

Classes of property, plant and equipment	Minimum life or rate ‎ (years)		Maximum life or rate ‎ (years)		life or average rate ‎ in years

Mining assets		3		10		5
Energy generating assets		5		10		6
Buildings		3		15		8
Supplies and accessories		2		10		3
Office equipment		5		5		5
Transport equipment		2		2		2
Network and communication equipment		2		10		5
IT equipment		2		8		5
Machinery, plant and equipment		1		15		7
Other property, plant and equipment		1		10		5