# Relationship history for MSHA mine 2000783

Current hierarchy: **Edward C  Levy Jr → Burroughs Materials Corp → Mickelson 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:** Mickelson Corp → Mickelson Sand & Gravel; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Blount Inc → Mickelson Sand & Gravel; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Blount Inc → Mickelson Corp; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Mickelson Sand & Gravel → Mickelson Sand & Gravel; 1986-03-01 to 2007-04-05; source msha-controller-operator-history
- **controller_controls_mine:** Edward C  Levy Jr et al → Mickelson Sand & Gravel; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward C  Levy Jr et al → Mickelson Sand & Gravel; 1986-03-01 to 2007-04-05; source msha-controller-operator-history
- **controller_controls_mine:** Edward C  Levy Jr et al → Mickelson Sand & Gravel; 1999-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Burroughs Materials Corp → Mickelson Sand & Gravel; 2007-04-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward C  Levy Jr et al → Burroughs Materials Corp; 2007-04-06 to current/open; source msha-controller-operator-history