Mining Interest, Plant and Equipment (Tables)

12 Months Ended

Apr. 30, 2020

Disclosure Of Property Plant And Equipment [Abstract]

Summary of Mining Interest, Plant and Equipment

	Mining Interest		Plant and Equipment Mining		Plant and Equipment Altiplano			Corporate Office Equipment			Total
Cost
Balance, April 30, 2018	$	64,358	$	23,176	$	6,654		$	692		$	94,880
Additions		1,338		1,055		92			25			2,510
Impairment write-down		-		-		(5,576	)		(2	)		(5,578	)
Effect of foreign exchange		2,734		1,238		876			-			4,848
Balance, April 30, 2019		68,430		25,469		2,046			715			96,660
Additions		1,613		251		-			10			1,874
Sale of Altiplano		-		-		(2,137	)		-			(2,137	)
Effect of foreign exchange		2,733		883		91			-			3,707
Balance, April 30, 2020	$	72,776	$	26,603	$	-		$	725		$	100,104
Depreciation
Balance, April 30, 2018	$	40,312	$	11,919	$	650		$	523		$	53,404
Depreciation for the year		1,923		1,768		118			90			3,899
Impairment write-down		-		-		(774	)		-			(774	)
Effect of foreign exchange		1,701		806		6			-			2,513
Balance, April 30, 2019		43,936		14,493		-			613			59,042
Depreciation for the year		1,374		1,851		-			78			3,303
Impairment write-down		-		-		-			-			-
Effect of foreign exchange		1,814		643		-			-			2,457
Balance, April 30, 2020	$	47,124	$	16,987	$	-		$	691		$	64,802
Carrying amounts
Balance, April 30, 2019	$	24,494	$	10,976	$	2,046		$	102		$	37,618
Balance, April 30, 2020	$	25,652	$	9,616	$	-		$	34		$	35,302