Schedule of Undiscounted Amounts of Estimated Cash Flows (Details) (USD $)	9 Months Ended
	Apr. 30, 2013
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 1	$ 4,106,195
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 2	$ 3,662,233
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 3	1.8
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 4	6.8
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 5	2.5
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 6	7.5
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 7	1.56%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 8	2.43%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 9	1.56%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 10	2.43%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 11	5.00%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 12	10.50%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 13	5.00%
Asset Retirement Obligations Schedule Of Undiscounted Amounts Of Estimated Cash Flows 14	10.50%