# Relationship history for MSHA mine 1900358

Current hierarchy: **Boston Sand & Gravel Company → Rosenfeld Concrete Corp → HOPEDALE PLANT**

- 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:** Rosenfeld Washed Sand & Stone Company → HOPEDALE PLANT; 1950-01-01 to 1985-08-12; source msha-controller-operator-history
- **controller_controls_mine:** Joseph  Rosenfeld → HOPEDALE PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph  Rosenfeld → Rosenfeld Washed Sand & Stone Company; 1950-01-01 to 1985-08-12; source msha-controller-operator-history
- **controller_controls_mine:** Boston Sand & Gravel Company → HOPEDALE PLANT; 1985-06-27 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rosenfeld Concrete Corp → HOPEDALE PLANT; 1985-08-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Boston Sand & Gravel Company → Rosenfeld Concrete Corp; 1985-08-13 to current/open; source msha-controller-operator-history