CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 469.3	$ 526.8
Accounts receivable	61.3	52.9
Accounts receivable-related parties	3.7	6.4
Product inventory	105.7	110.8
Material and supplies inventory	50.4	48.4
Prepaid expenses and other current assets	13.5	5.8
Income and mining taxes receivable	11.3	16.0
Restricted cash	25.0	37.1
Total current assets	740.2	804.2
Property, plant, equipment and development, net	2,622.6	2,538.9
Restricted cash	5.7	5.7
Reclamation deposits	29.5	30.1
Other assets	30.0	31.3
Total assets	3,428.0	3,410.2
Current liabilities
Accounts payable and accrued liabilities	105.8	128.5
Income, mining and other taxes payable	0.8	0.6
Current portion of long-term debt	16.4	16.6
Current portion of long-term capital lease obligations	18.6	14.1
Deferred income tax liabilities	7.0	5.9
Other current liabilities	13.7	13.8
Total current liabilities	162.3	179.5
Gold Stream deferred revenue	731.6	669.6
Long-term debt	918.1	921.8
Long-term capital lease obligations	74.5	58.0
Other liabilities	5.8	5.3
Asset retirement obligations	35.1	36.6
Deferred income tax liabilities	122.1	137.5
Total liabilities	2,049.5	2,008.3
Commitments and contingencies (Note 12)
Shareholders' equity
Common stock, no-par, 170,671,457 and 168,726,984 shares issued and outstanding as of March 31, 2013 and December 31, 2012, respectively	1,025.8	1,017.9
Additional paid-in capital	227.7	233.8
Retained earnings	93.2	92.3
Accumulated other comprehensive income	31.8	57.9
Total shareholders' equity	1,378.5	1,401.9
Total liabilities and shareholders' equity	$ 3,428.0	$ 3,410.2