# Relationship history for MSHA mine 1900308

Current hierarchy: **CRH PLC → Bushika Sand & Gravel Inc → Bushika 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:** Bushika Sand & Gravel Company → Bushika Sand & Gravel Inc; 1950-01-01 to 1984-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Bushika George & Frank → Bushika Sand & Gravel Inc; 1950-01-01 to 1984-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Bushika George & Frank → Bushika Sand & Gravel Company; 1950-01-01 to 1984-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Bushika Sand & Gravel Inc → Bushika Sand & Gravel Inc; 1984-12-01 to 2008-01-13; source msha-controller-operator-history
- **controller_controls_mine:** Joseph N.  Kroboth → Bushika Sand & Gravel Inc; 1984-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph N.  Kroboth → Bushika Sand & Gravel Inc; 1984-12-01 to 2008-01-13; source msha-controller-operator-history
- **operator_operates_mine:** Bushika Sand & Gravel Inc → Bushika Sand & Gravel Inc; 2008-01-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Bushika Sand & Gravel Inc; 2008-01-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Bushika Sand & Gravel Inc; 2008-01-14 to current/open; source msha-controller-operator-history