# Relationship history for MSHA mine 2002723

Current hierarchy: **Clifton  Halliday → Cliff's Sand & Gravel Inc → Cliff''s Sand & Gravel Inc**

- 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:** Cliff's Sand & Gravel Inc → Cliff''s Sand & Gravel Inc; 1984-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Clifton  Halliday et al → Cliff''s Sand & Gravel Inc; 1984-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Clifton  Halliday et al → Cliff's Sand & Gravel Inc; 1984-08-01 to current/open; source msha-controller-operator-history