# Relationship history for MSHA mine 0502677

Current hierarchy: **Thoms Judith A → J Thoms Construction Company Inc → Speer Development Pit**

- 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:** T P Construction Company Inc → Speer Development Pit; 1950-01-01 to 1985-08-13; source msha-controller-operator-history
- **controller_controls_mine:** Thoms Jack → Speer Development Pit; 1950-01-01 to 1985-08-13; source msha-controller-operator-history
- **controller_controls_operator:** Thoms Jack → T P Construction Company Inc; 1950-01-01 to 1985-08-13; source msha-controller-operator-history
- **operator_operates_mine:** J Thoms Construction Company Inc → Speer Development Pit; 1985-08-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Thoms Judith A → Speer Development Pit; 1985-08-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thoms Judith A → J Thoms Construction Company Inc; 1985-08-14 to current/open; source msha-controller-operator-history