# Relationship history for MSHA mine 4002088

Current hierarchy: **Bone John L Sr → Bone Coal Company Inc → Bone No 3 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

- **operator_operates_mine:** Micuron Coal Company → Bone No 3 Strip; 1976-06-25 to 1977-05-25; source msha-controller-operator-history
- **controller_controls_mine:** Engelhardt Donald → Bone No 3 Strip; 1976-06-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Engelhardt Donald → Micuron Coal Company; 1976-06-25 to 1977-05-25; source msha-controller-operator-history
- **operator_operates_mine:** Bone Coal Company Inc → Bone No 3 Strip; 1977-05-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bone John L Sr → Bone No 3 Strip; 1977-05-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bone John L Sr → Bone Coal Company Inc; 1977-05-26 to current/open; source msha-controller-operator-history