# Relationship history for MSHA mine 2000739

Current hierarchy: **Edward C  Levy Jr → Hersey Sand & Gravel → Hersey Sand & Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Blount Materials Corp → Hersey Sand & Gravel; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Blount Inc → Hersey Sand & Gravel; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Blount Inc → Blount Materials Corp; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Hersey Sand & Gravel → Hersey Sand & Gravel; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Edward C  Levy Jr et al → Hersey Sand & Gravel; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward C  Levy Jr et al → Hersey Sand & Gravel; 1986-03-01 to current/open; source msha-controller-operator-history