MAJOR SOURCES OF REVENUE (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
MAJOR SOURCES OF REVENUE
Minimum percentage required for qualifying as major operator	10.00%
Teck | Royalty revenue | Concentration of risk by operator
Major sources of revenue
Royalty revenue	$ 64,075	$ 43,604
Percentage of total royalty revenue	24.40%	20.10%
Vale Newfoundland & Labrador Limited | Royalty revenue | Concentration of risk by operator
Major sources of revenue
Royalty revenue	36,030	32,677
Percentage of total royalty revenue	13.70%	15.10%
Goldcorp, Inc. | Royalty revenue | Concentration of risk by operator
Major sources of revenue
Royalty revenue	31,407	23,094
Percentage of total royalty revenue	11.90%	10.70%
Barrick Gold | Royalty revenue | Concentration of risk by operator
Major sources of revenue
Royalty revenue	$ 21,891	$ 26,843	$ 30,624
Percentage of total royalty revenue	8.30%	12.40%	22.40%