Inventories, net

6 Months Ended

Jun. 30, 2021

Inventories

The following table provides the components of Inventories and the estimated recoverable gold ounces therein (dollars in thousands):


	June 30, 2021			December 31, 2020
	Amount		Gold Ounces	Amount		Gold Ounces
Current inventories:
Materials and supplies	$	7,211	—	$	6,449	—
Merrill-Crowe process plant	1,643		944	4,810		2,587
Carbon-in-column	1,724		1,015	299		166
Finished good (doré and off-site carbon)	8,509		5,010	1,309		710
Non-current inventories:
Stockpiles(1)	—		3,818	—		—
Total	$	19,087	10,787	$	12,867	3,463

(1)During 2021, the Company began stockpiling sulfide ore. The Company intends to use the stockpiles for testing related to the two-stage heap oxidation and leach process or for future processing. As of June 30, 2021, stockpiles had a value of $Nil due to the net realizable value analysis performed by the Company as discussed in the Mine site period costs section below.

As of June 30, 2021 and December 31, 2020, in-process inventories and finished goods inventories included $0.6 million and $0.3 million, respectively of capitalized depreciation and amortization costs.

The following table summarizes Ore on leach pads and the estimated recoverable gold ounces therein (dollars in thousands):


	June 30, 2021			December 31, 2020
	Amount		Gold Ounces	Amount		Gold Ounces
Ore on leach pads, current	$	37,664	21,723	$	38,041	21,869
Ore on leach pads, non-current	7,298		4,209	7,243		4,164
Total	$	44,962	25,932	$	45,284	26,033

As of both June 30, 2021 and December 31, 2020, Ore on leach pads included $1.8 million of capitalized depreciation and amortization costs. Additionally, as of June 30, 2021 and December 31, 2020 Ore on leach pads, non-current included $0.3 million and $0.4 million respectively, of capitalized depreciation and amortization costs.

Write-down of production inventories

The estimated recoverable gold ounces placed on the leach pads are periodically reconciled by comparing the related ore contents to the actual gold ounces recovered (metallurgical balancing). The Company did not record a Write-down of production inventories during the three and six months ended June 30, 2021.

During the three and six months ended June 30, 2020, based on metallurgical balancing results, the Company determined that 6,512 and 10,492 ounces of gold, respectively, that had been placed on the leach pads were no longer recoverable and recognized a Write-down of production inventories on the consolidated statements of operations, which included Production costs of $10.2 million and $16.7 million, respectively, and capitalized depreciation and amortization costs of $0.8 million and $1.2 million, respectively. The write-off of ounces during the three and six months ended June 30, 2020 were primarily due to mismanagement of the oxidation process, improper adjustments to variables in the oxidation process for changes in the ore type based on domain, and improper solution management. As a result, the Company determined it would recover less gold ounces than planned for those sections of the leach pads.

Mine site period costs

The following table summarize the components of Mine site period costs (dollars in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Production related costs	$	2,264	$	11,996	$	12,384	$	18,631
Capitalized depreciation and amortization	170		874		594		1,431
Total	$	2,434	$	12,870	$	12,978	$	20,062

Mine site period costs are generally the result of recurring or significant downtime or delays, unusually high levels of repairs, inefficient operations, overuse of processing reagents, inefficient cost-volume structures, or other unusual costs and activities, and cannot be recorded to production-related inventories based on the threshold established by the calculation of the estimated net realizable value per ounce of gold, which incorporates estimated future processing, refining, and selling costs, as well as the value for by-product silver.