Consolidated Statement of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue:
Coal sales		$ 56,922	$ 62,829	$ 123,709	$ 125,384
Other income (Note 7)		321	1,483	398	2,481
Total revenue		57,243	64,312	124,107	127,865
Costs and expenses:
Operating costs and expenses		38,874	44,079	85,514	83,771
DD&A		11,120	9,101	21,949	18,804
ARO accretion		291	214	573	421
Exploration costs		315	275	532	414
SG&A		2,474	6,578	6,364	9,236
Interest	[1]	4,315	3,342	7,023	6,433
Total costs and expenses		57,389	63,589	121,955	119,079
Income (loss) before income taxes		(146)	723	2,152	8,786
Income tax expense (benefit):
Current		(19)	1,357	(222)	1,374
Deferred		(104)	(1,023)	265	(391)
Total income tax expense (benefit)		(123)	334	43	983
Net income (loss)	[2]	$ (23)	$ 389	$ 2,109	$ 7,803
Net income (loss) per share (Note 9):
Basic and diluted (in Dollars per share)		$ 0.00	$ 0.01	$ 0.07	$ 0.25
Weighted average shares outstanding:
Basic and diluted (in Shares)		29,980	29,503	29,968	29,458
Net change in the estimated fair value of interest rate swap		$ 1,003	$ (20)	$ 844	$ (440)

[1] Interest expense for the first six months of 2018 and 2017 includes $844 and $(440), respectively, for the net change in the estimated fair value of our interest rate swaps. Such amounts were $1,003 and $(20) for the second quarter of 2018 and 2017, respectively.

[2] There is no material difference between net income and comprehensive income.