# Relationship history for MSHA mine 4605090

Current hierarchy: **Bias Ellet E → Bias Coal Company → No 1 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Bias Coal Company → No 1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bias Ellet E → No 1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bias Ellet E → Bias Coal Company; 1950-01-01 to current/open; source msha-controller-operator-history