# Relationship history for MSHA mine 4403677

Current hierarchy: **Layne Earnest → Black Bear Coal Corp → No 2 Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Black Coal Co → No 2 Mine; 1973-01-01 to 1976-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Black Coal Co → No 2 Mine; 1973-01-01 to 1976-09-14; source msha-controller-operator-history
- **controller_controls_operator:** Black Coal Co → Black Coal Co; 1973-01-01 to 1976-09-14; source msha-controller-operator-history
- **controller_controls_mine:** Layne Earnest → No 2 Mine; 1974-10-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Smith & Dotson Coal Company Inc → No 2 Mine; 1976-09-15 to 1977-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Smith Roger → No 2 Mine; 1976-09-15 to 1977-01-04; source msha-controller-operator-history
- **controller_controls_operator:** Smith Roger → Smith & Dotson Coal Company Inc; 1976-09-15 to 1977-01-04; source msha-controller-operator-history
- **operator_operates_mine:** Black Bear Coal Corp → No 2 Mine; 1977-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Layne Earnest → Black Bear Coal Corp; 1977-01-05 to current/open; source msha-controller-operator-history