# Relationship history for MSHA mine 0900591

Current hierarchy: **Reece Sand & Gravel Co → Reece Sand & Gravel Co → Dredge No 1**

- 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:** Reece Sand & Gravel Co → Dredge No 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Reece Sand & Gravel Co → Dredge No 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Reece Sand & Gravel Co → Reece Sand & Gravel Co; 1950-01-01 to current/open; source msha-controller-operator-history