Prepaid expenses (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Prepaid expenses [Abstract]

Disclosure of detailed information about prepaid expenses [Text Block]

(a)

This caption is made up as follows:

	2017		2016
	US$(000)		US$(000)

Prepaid rentals (b)		28,349		29,235
Prepaid insurances		12,401		6,055
Deferred costs of works for taxes		2,013		1,801
Deferred royalties and rentals of mining concessions		387		2,377
Other prepaid expenses		1,956		2,355

		45,106		41,823

Classification by maturity:
Current portion		17,551		11,392
Non-current portion		27,555		30,431

		45,106		41,823

(b)

This item corresponds to the balance of an original prepayment of US$31 million for the lease of hydraulic installations by the subsidiary Empresa de Generacion Huanza S.A. This prepayment is being charged to results during the life of the underlying assets (35 years) since January 2015.