CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 12,764	$ 16,281
Certificates of deposit	5,157	4,413
Accounts and other receivables, net of allowance for doubtful accounts of: $36,000 at December 31, 2017; $46,000 at September 30, 2017	1,820	1,414
Income taxes receivable	1,295	1,145
Investment held for sale	1,037	1,037
Other current assets	1,245	852
Total current assets	23,318	25,142
Income taxes receivable, net of current portion	460	0
Deferred income tax assets	219	300
Investments	2,056	2,209
Property and equipment	79,274	79,231
Accumulated depletion, depreciation, and amortization	(74,096)	(73,862)
Property and equipment, net	5,178	5,369
Total assets	31,231	33,020
Current liabilities:
Accounts payable	1,367	1,185
Accrued capital expenditures	378	348
Accrued compensation	380	390
Accrued operating and other expenses	1,046	1,386
Current portion of asset retirement obligation	1,092	1,231
Other current liabilities	465	258
Total current liabilities	4,728	4,798
Deferred rent	43	21
Liability for retirement benefits	4,180	4,150
Asset retirement obligation	5,391	5,632
Deferred income tax liabilities	227	236
Total liabilities	14,569	14,837
Commitments and contingencies
Equity:
Common stock, par value $0.50 per share; authorized, 20,000,000 shares: 8,445,060 issued at December 31, 2017 and September 30, 2017	4,223	4,223
Additional paid-in capital	1,351	1,350
Retained earnings	14,006	15,023
Accumulated other comprehensive loss, net	(1,040)	(1,058)
Treasury stock, at cost: 167,900 shares at December 31, 2017 and September 30, 2017	(2,286)	(2,286)
Total stockholders' equity	16,254	17,252
Non-controlling interests	408	931
Total equity	16,662	18,183
Total liabilities and equity	$ 31,231	$ 33,020