INCOME TAXES: - Tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets:
Inventories	$ 27.9	$ 27.6
Capitalized exploration expenses	17.5	20.1
U.S. foreign tax credit carryforward, net of FIN 48 liability	284.2	187.4
U.S. tax effect of Peruvian deferred tax liability	162.6	171.2
Property, plant and equipment	1.2
Reserves	108.9	42.3
Mexican tax on consolidated dividends	13.6	5.5
Prepaid	11.1	0.4
Other	29.7	22.4
Total deferred tax assets	656.7	476.9
Liabilities:
Property, plant and equipment		(18.5)
Deferred charges	(35.4)	(38.1)
Unremitted foreign earnings	(45.7)
Other	(10.9)	(2.1)
Total deferred tax liabilities	(92.0)	(58.7)
Total net deferred tax assets / (liabilities)	$ 564.7	$ 418.2

Represents the amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the methods used to account for capitalized exploration expenses for tax purposes and under generally accepted accounting principles.

No definition available.