# Relationship history for MSHA mine 1516787

Current hierarchy: **Williams Robert → Birchfield Mining Company Inc → No 3 Site**

- 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:** Williams Robert → No 3 Site; 1982-03-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Birchfield Mining Company Inc → No 3 Site; 1989-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Williams Robert → Birchfield Mining Company Inc; 1989-11-01 to current/open; source msha-controller-operator-history