# Relationship history for MSHA mine 4201813

Current hierarchy: **Sunnyside Mines Inc → Sunnyside Coal Company → Sunnyside Surface Operations**

- 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:** Kaiser Steel Corp → Sunnyside Surface Operations; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kaiser Coal Corp → Sunnyside Surface Operations; 1983-03-01 to 1988-08-08; source msha-controller-operator-history
- **controller_controls_operator:** Kaiser Steel Corp → Kaiser Coal Corp; 1983-03-01 to 1988-08-08; source msha-controller-operator-history
- **operator_operates_mine:** Badgers Unlimited Inc → Sunnyside Surface Operations; 1988-08-09 to 1988-12-01; source msha-controller-operator-history
- **controller_controls_mine:** Daye Walter → Sunnyside Surface Operations; 1988-08-09 to 1988-12-01; source msha-controller-operator-history
- **controller_controls_operator:** Daye Walter → Badgers Unlimited Inc; 1988-08-09 to 1988-12-01; source msha-controller-operator-history
- **operator_operates_mine:** Sunnyside Coal Company → Sunnyside Surface Operations; 1988-12-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sunnyside Mines Inc → Sunnyside Surface Operations; 1988-12-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sunnyside Mines Inc → Sunnyside Coal Company; 1988-12-02 to current/open; source msha-controller-operator-history