# Relationship history for MSHA mine 4201376

Current hierarchy: **Shumway Gary → Gary Shumway → Polar Mesa**

- 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:** Union Carbide Corp → Polar Mesa; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** C W Bunker & Company → Polar Mesa; 1950-01-01 to 1981-04-20; source msha-controller-operator-history
- **controller_controls_mine:** Bunker C W → Polar Mesa; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bunker C W → C W Bunker & Company; 1950-01-01 to 1981-04-20; source msha-controller-operator-history
- **operator_operates_mine:** Union Carbide Corp → Polar Mesa; 1981-04-21 to 1989-06-11; source msha-controller-operator-history
- **controller_controls_operator:** Union Carbide Corp → Union Carbide Corp; 1981-04-21 to 1989-06-11; source msha-controller-operator-history
- **operator_operates_mine:** Adolphus Moore → Polar Mesa; 1989-06-12 to 1990-07-29; source msha-controller-operator-history
- **controller_controls_mine:** Moore Adolphus → Polar Mesa; 1989-06-12 to 1990-07-29; source msha-controller-operator-history
- **controller_controls_operator:** Moore Adolphus → Adolphus Moore; 1989-06-12 to 1990-07-29; source msha-controller-operator-history
- **operator_operates_mine:** Gary Shumway → Polar Mesa; 1990-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Shumway Gary → Polar Mesa; 1990-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shumway Gary → Gary Shumway; 1990-07-30 to current/open; source msha-controller-operator-history