# Relationship history for MSHA mine 1510223

Current hierarchy: **Steele William Jr → Steele Brothers Construction Company → No 1 Surface/Refuse**

- 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:** United Coal Company Inc → No 1 Surface/Refuse; 1977-02-01 to 1986-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Clark W B → No 1 Surface/Refuse; 1977-02-01 to 1986-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Clark W B → United Coal Company Inc; 1977-02-01 to 1986-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Steele Brothers Construction Company → No 1 Surface/Refuse; 1986-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steele William Jr → No 1 Surface/Refuse; 1986-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steele William Jr → Steele Brothers Construction Company; 1986-04-03 to current/open; source msha-controller-operator-history