5. PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment, including coal properties and mine development and construction costs, as of September 30, 2015 and December 31, 2014 are summarized by major classification as follows:


	Useful Lives	September 30, 2015	December 31, 2014
		(in thousands)
Land and land improvements		$ 18,799	$ 18,845
Mining and other equipment and related facilities	2 - 20 Years	333,481	336,951
Mine development costs	1 - 15 Years	76,285	79,536
Coal properties	1 - 15 Years	219,018	215,325
Oil and natural gas properties		-	8,093
Construction work in process		3,045	4,912
Total		650,628	663,662
Less accumulated depreciation, depletion and amortization		(288,328)	(280,225)
Net		$ 362,300	$ 383,437

Depreciation expense for mining and other equipment and related facilities, depletion expense for coal properties and oil and natural gas properties, amortization expense for mine development costs, amortization expense for intangible assets and amortization expense for asset retirement costs for the three and nine months ended September 30, 2015 and 2014 were as follows:


	Three Months Ended September 30,		Nine Months Ended September 30,
	2015	2014	2015	2014
	(in thousands)
Depreciation expense-mining and other equipment and related facilities	$ 7,202	$ 7,931	$ 22,171	$ 22,652
Depletion expense for coal properties and oil and natural gas properties	701	1,173	2,234	3,672
Amortization expense for mine development costs	465	471	1,545	1,258
Amortization expense for intangible assets	20	20	60	61
Amortization expense for asset retirement costs	(140)	32	(315)	146
Total depreciation, depletion and amortization	$ 8,248	$ 9,627	$ 25,695	$ 27,789

Long-Lived Asset Impairments

On October 30, 2015, the Partnership executed a binding letter of intent with a third party for the purchase of the Partnership’s Deane mining complex, subject to normal closing conditions. The Partnership’s Deane mining complex is located in eastern Kentucky and includes one underground mine that is currently idle. The infrastructure at the Deane mining complex consists of a preparation plant and a unit train loadout facility. The contemplated sale of the Deane complex would transfer the underground mine, related equipment, the preparation plant and loadout facility, while the Partnership would retain the mineral rights for the 39.3 million tons of proven and probable steam coal reserves at this complex. The contemplated transaction would also include a royalty agreement with the third party pursuant to which the Partnership would collect future royalties for coal mined and sold from the Deane complex. The contemplated sale of the Deane complex would also relieve the Partnership of significant reclamation liabilities and bonding requirements. The Partnership evaluated the appropriate held for sale accounting criteria to determine if the Deane mining complex should be classified as held for sale as of September 30, 2015. Based on this evaluation, the Partnership determined the Deane mining complex met the held for sale criteria at September 30, 2015 and, accordingly, the Deane mining complex asset group was written down to its estimated fair value of $2.0 million. Due to the determination that the Deane mining complex met the held for sale criteria, the Partnership recorded an impairment charge of approximately $2.3 million for the three and nine months ended September 30, 2015 and the Partnership will cease depreciation of this asset group in future periods. As of September 30, 2015, the Partnership classified approximately $8.8 million of assets and approximately $6.8 million of liabilities related to the Deane complex as held for sale on its unaudited condensed consolidated statements of financial position.

In August 2015, the Partnership completed the sale of its oil and natural gas investment of approximately 1,900 net mineral acres in the Cana Woodford region of western Oklahoma. The Partnership received a total of approximately $5.7 million in proceeds from the sale of the Cana Woodford oil and natural gas mineral rights. In the second quarter of 2015, the Partnership evaluated the appropriate held for sale accounting criteria to determine if the Cana Woodford mineral rights should be classified as held for sale as of June 30, 2015. Based on this evaluation, the Partnership determined these mineral rights met the held for sale criteria at June 30, 2015 and, accordingly, these mineral rights were written down to their estimated fair value of $5.8 million. Due to the determination that the mineral rights met the held for sale criteria, the Partnership recorded an impairment charge of approximately $2.2 million for the Cana Woodford mineral rights during the second quarter of 2015.

The Partnership had a steam coal surface mine operation in eastern Kentucky (referred to as “Bevins Branch”) in its Central Appalachia segment that was idled during mid-2014 as that location’s contract with its single customer expired at that time. In May 2015, the Partnership finalized a contractual agreement with a third party to assume the Bevins Branch operation. The contractual agreement had the third party assume the Bevins Branch operation where the only financial compensation the Partnership received is a future override royalty and the assumption of the reclamation obligations by the buyer. The closing of the transaction also allowed the Partnership to avoid the ongoing maintenance costs of this operation. The Partnership reviewed the Bevins Branch operation as of December 31, 2014 in accordance with the accounting guidance for long-lived asset impairment and recorded total asset impairment and related charges of $8.3 million for the Bevins Branch operation for the year ended December 31, 2014. As of September 30, 2015, the Partnership removed the approximately $2.3 million of remaining assets and any related liabilities that had been previously classified as held for sale on its unaudited condensed consolidated statements of financial position.