# Relationship history for MSHA mine 1600921

Current hierarchy: **Greer George → La Salle'S Big G Gravel Company Inc → La Salle'S Big G Gravel Company Incorpor**

- 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:** Smith Gravel Company → La Salle'S Big G Gravel Company Incorpor; 1950-01-01 to 1978-10-24; source msha-controller-operator-history
- **controller_controls_mine:** Smith Gravel Company → La Salle'S Big G Gravel Company Incorpor; 1950-01-01 to 1978-10-24; source msha-controller-operator-history
- **controller_controls_operator:** Smith Gravel Company → Smith Gravel Company; 1950-01-01 to 1978-10-24; source msha-controller-operator-history
- **operator_operates_mine:** La Salle'S Big G Gravel Company Inc → La Salle'S Big G Gravel Company Incorpor; 1978-10-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Greer George → La Salle'S Big G Gravel Company Incorpor; 1978-10-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Greer George → La Salle'S Big G Gravel Company Inc; 1978-10-25 to current/open; source msha-controller-operator-history