# Relationship history for MSHA mine 3303835

Current hierarchy: **Ronald E  Watson → Watson Gravel Inc → Watson Gravel Inc (Kilby Plant)**

- 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

- **controller_controls_mine:** Ronald E  Watson → Watson Gravel Inc (Kilby Plant); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Watson Gravel Inc → Watson Gravel Inc (Kilby Plant); 1981-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald E  Watson → Watson Gravel Inc; 1981-06-01 to current/open; source msha-controller-operator-history