# Relationship history for MSHA mine 1507675

Current hierarchy: **Mid Con Corp & Royalton Coal Corp Inc → Royalton Coal Corp Inc → No 1 Surface**

- 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:** Donn A  Chickering → No 1 Surface; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Branham & Baker Coal Company Inc → No 1 Surface; 1974-11-01 to 1975-09-18; source msha-controller-operator-history
- **controller_controls_operator:** Donn A  Chickering → Branham & Baker Coal Company Inc; 1974-11-01 to 1975-09-18; source msha-controller-operator-history
- **operator_operates_mine:** Royalton Coal Corp Inc → No 1 Surface; 1975-09-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mid Con Corp & Royalton Coal Corp Inc → No 1 Surface; 1975-09-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mid Con Corp & Royalton Coal Corp Inc → Royalton Coal Corp Inc; 1975-09-19 to current/open; source msha-controller-operator-history