The following summarizes our inventory, recorded at the lower of weighted average cost or estimated net realizable value as of December 31, 2018, and 2017, respectively (in thousands):



	December 31,
	2018		2017
Finished goods product inventory	$	48,370	$	54,577
In-process mineral inventory	24,325		19,822
Total product inventory	72,695		74,399
Current parts inventory, net	9,351		8,727
Total current inventory, net	82,046		83,126
Long-term parts inventory, net	30,031		30,611
Total inventory, net	$	112,077	$	113,737