# Relationship history for MSHA mine 3502857

Current hierarchy: **Mc Gill Robert L → R S Burch Company → Table Mountain 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Robert G  Wienert → Table Mountain Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mc Gill Robert L → Table Mountain Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Yaquina Head Quarries Inc → Table Mountain Pit; 1978-03-09 to 1980-06-29; source msha-controller-operator-history
- **controller_controls_operator:** Robert G  Wienert → Yaquina Head Quarries Inc; 1978-03-09 to 1980-06-29; source msha-controller-operator-history
- **operator_operates_mine:** R S Burch Company → Table Mountain Pit; 1980-06-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mc Gill Robert L → R S Burch Company; 1980-06-30 to current/open; source msha-controller-operator-history