# Relationship history for MSHA mine 4601493

Current hierarchy: **Brook Coal Company → Reliable Coal Corp → Masontown Mine**

- 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:** Reliable Coal Corp → Masontown Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brook Coal Company → Masontown Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brook Coal Company → Reliable Coal Corp; 1950-01-01 to current/open; source msha-controller-operator-history