Fixed Assets and Asset Retirement Obligations

12 Months Ended

Dec. 31, 2012

6. Fixed Assets and Asset Retirement Obligations

Fixed Assets

Fixed assets consisted of the following:



	December 31,
	2012			2011
Pipelines and related assets	$	226,831		$	167,865
Machinery and equipment	87,502			46,233
Transportation equipment	21,170			21,732
Marine vessels	298,054			262,216
Land, buildings and improvements	15,606			13,140
Office equipment, furniture and fixtures	4,964			3,778
Construction in progress	52,541			14,236
Other	16,557			11,938
Fixed assets, at cost	723,225			541,138
Less: Accumulated depreciation	(157,944		)	(124,213		)
Net fixed assets	$	565,281		$	416,925

Depreciation expense was $37.4 million, $27.5 million and $22.5 million for the years ended December 31, 2012, 2011, and 2010, respectively.

Asset Retirement Obligations

A reconciliation of our liability for asset retirement obligations is as follows:



December 31, 2010	$	5,179
Liabilities incurred and assumed in the current period	349
Accretion expense	372
December 31, 2011	5,900
Liabilities incurred and assumed in the current period	5,995
Accretion expense	800
December 31, 2012	$	12,695