| In millions, except per share items | Jun-30-23 | Mar-31-23 | Dec-31-22 | Sep-30-22 | Jun-30-22 | Mar-31-22 | Dec-31-21 | Sep-30-21 |
| | 10-Q | 10-Q | 10-K | 10-Q | 10-Q | 10-Q | 10-K | 10-Q |
| OPERATING ACTIVITIES: | | | | | | | | |
| Net income (loss) | 16.9 | 22.1 | 30.0 | -11.9 | -3.4 | -10.1 | -7.7 | 4.0 |
| Deferred income taxes | 1.5 | 2.9 | 0.9 | 0.6 | 0.4 | -0.2 | 2.7 | -1.4 |
| Equity income (loss) – Sunrise Energy | 0.2 | -0.1 | 0.1 | -0.2 | -0.2 | -0.2 | -0.2 | -0.1 |
| Cash distribution - Sunrise Energy | | 0.6 | | | | | | |
| Depreciation, depletion and amortization | 17.2 | 18.0 | 15.0 | 11.2 | 11.2 | 9.5 | 10.1 | 9.8 |
| Loss on sale of assets | 0.0 | 0.0 | 0.1 | | -0.4 | 0.1 | | |
| Change in fair value of interest rate swaps | | | | | | | | |
| Amortization of debt issuance costs | 1.0 | 1.2 | 1.1 | 1.0 | 0.8 | 0.7 | 0.7 | 0.7 |
| Asset retirement obligations accretion | 0.5 | 0.5 | 0.3 | 0.3 | 0.3 | 0.2 | 0.4 | 0.4 |
| Cash paid on asset retirement obligation reclamation | -0.6 | -0.4 | -0.7 | -1.3 | -0.5 | -0.7 | | |
| Stock-based compensation | 0.8 | 1.2 | 1.0 | 0.1 | 0.1 | 0.1 | 0.2 | 0.3 |
| Provision for loss on customer contracts | | | | | | 0.2 | | |
| Amortization of contract asset and contract liabilities | -6.6 | -15.6 | -19.7 | | | | | |
| Other | 0.3 | 0.5 | -0.2 | 0.5 | 0.3 | 0.2 | -0.5 | 0.0 |
| Change in operating assets and liabilities: | | | | | | | | |
| Accounts receivable | 11.7 | -3.3 | -13.1 | 0.4 | -1.7 | -1.8 | 2.9 | -2.1 |
| Inventory | -5.3 | -4.0 | -19.8 | 0.1 | -5.0 | -1.1 | 3.6 | 21.0 |
| Parts and supplies | -2.6 | -2.9 | -1.3 | -2.7 | -0.8 | -1.5 | -0.2 | -0.5 |
| Prepaid expenses | -0.1 | 0.4 | -3.6 | -3.1 | -0.9 | 1.6 | -0.6 | -4.5 |
| Accounts payable and accrued liabilities | -13.9 | 2.0 | 14.7 | 5.3 | -2.5 | 6.6 | 1.9 | 3.3 |
| Deferred revenue | -2.9 | 3.0 | | | | | | |
| Cash provided by operating activities | 18.1 | 26.1 | 40.2 | 13.7 | -2.7 | 3.0 | 10.9 | 24.1 |
| |
| INVESTING ACTIVITIES: | | | | | | | | |
| Capital expenditures | -17.1 | -13.5 | -15.7 | -15.4 | -13.8 | -9.1 | -10.0 | -7.2 |
| Proceeds from sale of equipment | 0.0 | 0.0 | -0.1 | | 0.6 | 0.1 | | |
| Cash used in investing activities | -17.1 | -13.5 | -15.8 | -15.4 | -13.2 | -9.0 | -9.5 | -7.2 |
| |
| FINANCING ACTIVITIES: | | | | | | | | |
| Payments on bank debt | -10.0 | -27.0 | -42.5 | -21.0 | -5.5 | -9.2 | -9.2 | -18.2 |
| Borrowings of bank debt | 9.0 | 17.0 | 14.0 | 4.0 | 16.2 | 17.5 | 6.0 | 3.0 |
| Issuance of convertible note | | | | | 1.0 | | | |
| Issuance of related party convertible notes payable | | | | | 9.0 | | | |
| Debt issuance costs | 0.0 | -1.6 | | -1.5 | | -0.6 | | |
| Taxes paid on vesting of RSUs | | -1.1 | | | | | -0.3 | |
| Cash (used in) provided by financing activities | -1.0 | -12.7 | -28.5 | -0.1 | 20.7 | 7.7 | -3.5 | -15.2 |
| (Decrease) increase in cash, cash equivalents, and restricted cash | 0.0 | -0.1 | | | 4.8 | 1.7 | | |
| |
| CASH, CASH EQUIVALENTS, AND RESTRICTED CASH CONSIST OF THE FOLLOWING: | | | | | | | | |
| Cash and cash equivalents | | | | | | | | |
| Restricted cash | | | | | | | | |
| SUPPLEMENTAL CASH FLOW INFORMATION: | | | | | | | | |
| Cash paid for interest | 1.9 | 3.1 | 3.3 | 0.7 | 2.0 | 2.0 | 2.0 | 2.3 |
| SUPPLEMENTAL NON-CASH FLOW INFORMATION: | | | | | | | | |
| Change in capital expenditures included in accounts payable and prepaid expense | 0.3 | 0.1 | 1.0 | 0.4 | 1.4 | 0.6 | 2.7 | 2.2 |
| Debt issuance costs included in accounts payable and accrued liabilities | | | | | 0.9 | | | |
| Convertible notes payable and related party convertible notes payable converted to common stock | | | | | 10.0 | | | |