# Relationship history for MSHA mine 3607525

Current hierarchy: **Petrof Emery → Elk Contracting Company → Elk No 1**

- 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:** Petrof Joseph → Elk No 1; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Petrof Contracting Company → Elk No 1; 1984-01-01 to 1984-09-17; source msha-controller-operator-history
- **controller_controls_operator:** Petrof Joseph → Petrof Contracting Company; 1984-01-01 to 1984-09-17; source msha-controller-operator-history
- **operator_operates_mine:** Elk Contracting Company → Elk No 1; 1984-09-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Petrof Emery → Elk No 1; 1984-09-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Petrof Emery → Elk Contracting Company; 1984-09-18 to current/open; source msha-controller-operator-history