Inventories, Including Long-Term Mill and Leach Stockpiles

9 Months Ended

Sep. 30, 2021

Inventories, Including Long-Term Mill and Leach Stockpiles

INVENTORIES, INCLUDING LONG-TERM MILL AND LEACH STOCKPILES

The components of inventories follow (in millions):


	September 30, 2021		December 31, 2020
Current inventories:
Total materials and supplies, neta	$	1,617	$	1,594

Mill stockpiles	$	209	$	205
Leach stockpiles	877		809
Total current mill and leach stockpiles	$	1,086	$	1,014

Raw materials (primarily concentrate)	$	437	$	366
Work-in-process	184		174
Finished goods	796		745
Total product	$	1,417	$	1,285

Long-term inventories:
Mill stockpiles	$	223	$	223
Leach stockpiles	1,227		1,240
Total long-term mill and leach stockpilesb	$	1,450	$	1,463

a.Materials and supplies inventory was net of obsolescence reserves totaling $37 million at September 30, 2021, and $32 million at December 31, 2020.

b.Estimated metals in stockpiles not expected to be recovered within the next 12 months.

FCX recorded charges for metals inventory adjustments totaling $15 million for the first nine months of 2021 primarily related to a leach stockpile adjustment. Net realizable value inventory adjustments to decrease metals inventory carrying values totaled $92 million for the first nine months of 2020 associated with lower market prices for copper ($58 million) and molybdenum ($34 million). Refer to Note 9 for metals inventory adjustments by business segment.

Morenci Stockpile Recoveries. In accordance with FCX's policy, processes and recovery rates for mill and leach stockpiles are monitored regularly, and recovery rate estimates are adjusted periodically as additional information becomes available and as related technology changes. Adjustments to recovery rates will typically result in a future impact to the value of the material removed from the stockpiles at a revised weighted-average cost per pound of recoverable copper.

Expected copper recovery rates for leach stockpiles are determined using small-scale laboratory tests, small- to large-scale column testing (which simulates the production process), historical trends and other factors, including mineralogy of the ore and rock type. Total copper recovery in leach stockpiles can vary significantly from a low percentage to more than 90 percent depending on several variables, including processing methodology, processing variables, mineralogy and particle size of the rock. For newly placed material on active stockpiles, as much as 80 percent of the total copper recovery may occur during the first year, and the remaining copper may be recovered over many years.

Over the last three years, FCX's Morenci mine has experienced improved recoveries and following an analysis of column testing results to date, Morenci concluded it had sufficient evidence to increase its estimated recovery rate for certain of its leach stockpiles effective July 1, 2021. As a result of the revised recovery rate, Morenci increased its estimated recoverable copper in leach stockpiles, net to its joint venture interest, by 191 million pounds. The effect of this change in estimate reduced site production and delivery costs and increased net income by $52 million ($0.04 per share) in the third quarter and first nine months of 2021.