# Relationship history for MSHA mine 1900553

Current hierarchy: **S M Lorusso & Sons Inc → Lorusso-Bristol Stone Corporation → Lorusso-Bristol Stone Corporation**

- 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:** Marshfield Sand & Gravel Inc → Lorusso-Bristol Stone Corporation; 1950-01-01 to 1980-06-12; source msha-controller-operator-history
- **controller_controls_mine:** Sylvester A  Ray → Lorusso-Bristol Stone Corporation; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sylvester A  Ray → Marshfield Sand & Gravel Inc; 1950-01-01 to 1980-06-12; source msha-controller-operator-history
- **operator_operates_mine:** Lorusso-Bristol Stone Corporation → Lorusso-Bristol Stone Corporation; 1980-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** S M Lorusso & Sons Inc → Lorusso-Bristol Stone Corporation; 1980-06-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** S M Lorusso & Sons Inc → Lorusso-Bristol Stone Corporation; 1980-06-13 to current/open; source msha-controller-operator-history