Note 6 - Workers' compensation and occupational disease	12 Months Ended
Dec. 31, 2021
Notes To Financial Statements
WORKERS' COMPENSATION AND OCCUPATIONAL DISEASE OBLIGATIONS	NOTE 6—WORKERS’ COMPENSATION AND OCCUPATIONAL DISEASE OBLIGATIONS We are self-insured for certain losses relating to workers’ compensation claims and occupational disease obligations under the Federal Mine Safety and Health Act of 1969, as amended. We purchase insurance coverage to reduce our exposure to significant levels of these claims. Self-insured losses are accrued based upon estimates of the aggregate liability for uninsured claims incurred as of the balance sheet date using current and historical claims experience and certain actuarial assumptions. The occupational disease benefit obligation represents the present value of the actuarially computed present and future liabilities for such benefits over the employees’ applicable years of service using a discount rate of 3.26%. As of December 31, 2021, the estimated aggregate liability for uninsured claims totaled $3.9 million, including $1.4 million of occupational disease obligations. Of the aggregate liability, $2.4 million was included in other long-term liabilities within the consolidated balance sheets. As of December 31, 2020, the estimated aggregate liability for uninsured claims totaled $1.7 million, including $0.9 million in other long-term liabilities.

Note 6 - Workers' compensation and occupational disease

12 Months Ended

Dec. 31, 2021

WORKERS' COMPENSATION AND OCCUPATIONAL DISEASE OBLIGATIONS

NOTE 6—WORKERS’ COMPENSATION AND OCCUPATIONAL DISEASE OBLIGATIONS

We are self-insured for certain losses relating to workers’ compensation claims and occupational disease obligations under the Federal Mine Safety and Health Act of 1969, as amended. We purchase insurance coverage to reduce our exposure to significant levels of these claims. Self-insured losses are accrued based upon estimates of the aggregate liability for uninsured claims incurred as of the balance sheet date using current and historical claims experience and certain actuarial assumptions. The occupational disease benefit obligation represents the present value of the actuarially computed present and future liabilities for such benefits over the employees’ applicable years of service using a discount rate of 3.26%.

As of December 31, 2021, the estimated aggregate liability for uninsured claims totaled $3.9 million, including $1.4 million of occupational disease obligations. Of the aggregate liability, $2.4 million was included in other long-term liabilities within the consolidated balance sheets. As of December 31, 2020, the estimated aggregate liability for uninsured claims totaled $1.7 million, including $0.9 million in other long-term liabilities.