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Note 12 - Asset Retirement Obligations - Undiscounted Amounts of Estimated Cash Flows for the Next Five Fiscal Years and Beyond (Details) - USD ($)
Apr. 30, 2021
Jul. 31, 2020
Fiscal 2022  
Fiscal 2023  
Fiscal 2024  
Fiscal 2025  
Fiscal 2026  
Remaining balance 8,221,018  
Undiscounted Amount of Estimated Cash Flows $ 8,221,018 $ 8,221,018