# Relationship history for MSHA mine 3606436

Current hierarchy: **Petrof Joseph → Petrof Contracting Company → Beaver Valley Strip 2**

- 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 → Beaver Valley Strip 2; 1974-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Petrof Contracting Company → Beaver Valley Strip 2; 1977-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Petrof Joseph → Petrof Contracting Company; 1977-06-01 to current/open; source msha-controller-operator-history