# Relationship history for MSHA mine 3002912

Current hierarchy: **Vigliarolo Michael & Frank Jr → Medford Sand & Gravel Corp → MEDFORD SAND & GRAVEL CORP.**

- 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:** Medford Sand & Gravel Corp → MEDFORD SAND & GRAVEL CORP.; 1989-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Vigliarolo Michael & Frank Jr Et Al → MEDFORD SAND & GRAVEL CORP.; 1989-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vigliarolo Michael & Frank Jr Et Al → Medford Sand & Gravel Corp; 1989-09-01 to current/open; source msha-controller-operator-history