# Relationship history for MSHA mine 0100419

Current hierarchy: **Drummond Company Inc → Drummond Coal Company → No 350 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

- **controller_controls_mine:** Drummond Company Inc → No 350 Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Marigold Coal Company Inc → No 350 Pit; 1950-01-01 to 1974-01-20; source msha-controller-operator-history
- **controller_controls_mine:** Marigold Coal Company Inc → No 350 Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marigold Coal Company Inc → Marigold Coal Company Inc; 1950-01-01 to 1974-01-20; source msha-controller-operator-history
- **operator_operates_mine:** Drummond Coal Company → No 350 Pit; 1974-01-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Drummond Company Inc → Drummond Coal Company; 1974-01-21 to current/open; source msha-controller-operator-history