# Relationship history for MSHA mine 2200042

Current hierarchy: **Talbert Charles R → W F Brown & Company Inc → Walker 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:** Dickey Company → Walker Mine; 1950-01-01 to 1978-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Hepworth Plc → Walker Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hepworth Plc → Dickey Company; 1950-01-01 to 1978-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Talbert Charles R → Walker Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** W F Brown & Company Inc → Walker Mine; 1978-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Talbert Charles R → W F Brown & Company Inc; 1978-08-01 to current/open; source msha-controller-operator-history