# Relationship history for MSHA mine 3605068

Current hierarchy: **Martha Coal Company Inc → Martha Coal Co Inc → Eighty Four Strip**

- 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

- **controller_controls_mine:** Seamon Roland → Eighty Four Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Mark Iv Coal Co → Eighty Four Strip; 1974-03-28 to 1975-08-15; source msha-controller-operator-history
- **controller_controls_operator:** Seamon Roland → Mark Iv Coal Co; 1974-03-28 to 1975-08-15; source msha-controller-operator-history
- **operator_operates_mine:** Martha Coal Co Inc → Eighty Four Strip; 1975-08-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martha Coal Company Inc → Eighty Four Strip; 1975-08-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martha Coal Company Inc → Martha Coal Co Inc; 1975-08-16 to current/open; source msha-controller-operator-history