# Relationship history for MSHA mine 4606266

Current hierarchy: **Massey Energy Company → Robinson-Phillips Coal Company Inc → Big Bear #4**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Massey Energy Company → Big Bear #4; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Massey Energy Company → Big Bear #4; 1978-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Big Bear Mining Company Inc → Big Bear #4; 1980-10-01 to 1988-02-21; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Big Bear Mining Company Inc; 1980-10-01 to 1988-02-21; source msha-controller-operator-history
- **operator_operates_mine:** P L C Equipment Company Inc → Big Bear #4; 1988-02-22 to 1990-01-30; source msha-controller-operator-history
- **controller_controls_mine:** Church Patricia → Big Bear #4; 1988-02-22 to 1990-01-30; source msha-controller-operator-history
- **controller_controls_operator:** Church Patricia → P L C Equipment Company Inc; 1988-02-22 to 1990-01-30; source msha-controller-operator-history
- **operator_operates_mine:** Robinson-Phillips Coal Company Inc → Big Bear #4; 1990-01-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Robinson-Phillips Coal Company Inc; 1990-01-31 to current/open; source msha-controller-operator-history