# Relationship history for MSHA mine 2500750

Current hierarchy: **Werner David → H & M Equipment Company → Mader 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:** H & M Equipment Company Inc → Mader Pit; 1950-01-01 to 1988-06-20; source msha-controller-operator-history
- **controller_controls_mine:** Bauer Don J → Mader Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bauer Don J → H & M Equipment Company Inc; 1950-01-01 to 1988-06-20; source msha-controller-operator-history
- **operator_operates_mine:** H & M Equipment Company → Mader Pit; 1988-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Werner David → Mader Pit; 1988-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Werner David → H & M Equipment Company; 1988-06-21 to current/open; source msha-controller-operator-history