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Asset Retirement Obligation - Schedule of Asset Retirement Obligation (Details) - USD ($)
3 Months Ended 6 Months Ended
Oct. 31, 2019
Oct. 31, 2018
Oct. 31, 2019
Oct. 31, 2018
Asset Retirement Obligation Disclosure [Abstract]        
Balance, beginning of period     $ 88,746 $ 81,885
Addition and changes in estimates    
Accretion expense $ 2,191 $ 1,467 4,331 2,721
Balance, end of period $ 93,077 $ 79,059 $ 93,077 $ 79,059