# Relationship history for MSHA mine 3303979

Current hierarchy: **Roger J  Schuck → Rockwell Sand & Gravel Inc → ROCKWELL 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

- **controller_controls_mine:** Began Joe A → ROCKWELL SAND & GRAVEL, INC.; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Northern Ohio Materials Inc → ROCKWELL SAND & GRAVEL, INC.; 1984-08-01 to 1992-10-20; source msha-controller-operator-history
- **controller_controls_operator:** Began Joe A → Northern Ohio Materials Inc; 1984-08-01 to 1992-10-20; source msha-controller-operator-history
- **operator_operates_mine:** Northern Ohio Materials Inc → ROCKWELL SAND & GRAVEL, INC.; 1992-10-21 to 1996-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Bulk Materials Inc → ROCKWELL SAND & GRAVEL, INC.; 1992-10-21 to 1998-10-12; source msha-controller-operator-history
- **controller_controls_operator:** Bulk Materials Inc → Northern Ohio Materials Inc; 1992-10-21 to 1996-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Rockwell Sand & Gravel Inc → ROCKWELL SAND & GRAVEL, INC.; 1996-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Roger J  Schuck → ROCKWELL SAND & GRAVEL, INC.; 1996-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roger J  Schuck → Rockwell Sand & Gravel Inc; 1996-04-01 to current/open; source msha-controller-operator-history