# Relationship history for MSHA mine 0202163

Current hierarchy: **Woodrow J  Whitehurst; Joseph F  Guinn → Ajax Contracting Company Inc → Ajax Sand & Rock**

- 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:** Ajax Contracting Company Inc → Ajax Sand & Rock; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Joseph F  Guinn et al → Ajax Sand & Rock; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph F  Guinn et al → Ajax Contracting Company Inc; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Woodrow J  Whitehurst et al → Ajax Contracting Company Inc; 1983-09-01 to current/open; source msha-controller-operator-history