# Relationship history for MSHA mine 4501994

Current hierarchy: **Don  Merlino; Gary  Merlino → Kangley Sand & Gravel → Kangley Pit**

- 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:** Stoneway Concrete Inc → Kangley Pit; 1950-01-01 to 1985-09-05; source msha-controller-operator-history
- **controller_controls_mine:** Kent Highlands Inc → Kangley Pit; 1950-01-01 to 1985-09-05; source msha-controller-operator-history
- **controller_controls_operator:** Kent Highlands Inc → Stoneway Concrete Inc; 1950-01-01 to 1985-09-05; source msha-controller-operator-history
- **operator_operates_mine:** Kangley Sand & Gravel → Kangley Pit; 1985-09-06 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gary  Merlino et al → Kangley Pit; 1985-09-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary  Merlino et al → Kangley Sand & Gravel; 1985-09-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don  Merlino et al → Kangley Sand & Gravel; 1985-09-06 to current/open; source msha-controller-operator-history