Fixed Assets, Mineral Leaseholds, and Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2020

Fixed assets, net consisted of the following:


	September 30, 2020		December 31, 2019
Crude oil pipelines and natural gas pipelines and related assets	$	2,880,802	$	2,891,489
Alkali facilities, machinery, and equipment	614,403		591,547
Onshore facilities, machinery, and equipment	264,763		640,376
Transportation equipment	19,336		19,864
Marine vessels	993,346		979,171
Land, buildings and improvements	217,770		238,451
Office equipment, furniture and fixtures	21,993		22,645
Construction in progress	155,099		115,162
Other	41,891		41,891
Fixed assets, at cost	5,209,403		5,540,596
Less: Accumulated depreciation	(1,295,654)		(1,246,121)
Net fixed assets	$	3,913,749	$	4,294,475

Our Mineral Leaseholds, relating to our Alkali Business, consist of the following:


	September 30, 2020		December 31, 2019
Mineral leaseholds	$	566,019	$	566,019
Less: Accumulated depletion	(12,602)		(10,194)
Mineral leaseholds, net of accumulated depletion	$	553,417	$	555,825

Our depreciation and depletion expense for the periods presented was as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Depreciation expense	$	62,499	$	77,228	$	206,830	$	222,106
Depletion expense	604		1,204		2,408		3,488

The following table presents information regarding our AROs since December 31, 2019:


ARO liability balance, December 31, 2019	$	175,081
Accretion expense	6,809
Changes in estimate	609


Settlements	(11,547)

ARO liability balance, September 30, 2020	$	170,952

With respect to our AROs, the following table presents our estimate of accretion expense for the periods indicated: