# Relationship history for MSHA mine 1600459

Current hierarchy: **Dyson Alton → Vermilion Sand & Gravel Inc → Vermilion Sand & Gravel Incorporated**

- 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:** Acadian Sand & Limestone Inc → Vermilion Sand & Gravel Incorporated; 1950-01-01 to 1980-10-07; source msha-controller-operator-history
- **controller_controls_mine:** Caldwell Alex → Vermilion Sand & Gravel Incorporated; 1950-01-01 to 1980-10-07; source msha-controller-operator-history
- **controller_controls_operator:** Caldwell Alex → Acadian Sand & Limestone Inc; 1950-01-01 to 1980-10-07; source msha-controller-operator-history
- **operator_operates_mine:** Ingram Aggregates Inc → Vermilion Sand & Gravel Incorporated; 1980-10-08 to 1983-08-24; source msha-controller-operator-history
- **controller_controls_mine:** Ingram Industries Inc → Vermilion Sand & Gravel Incorporated; 1980-10-08 to 1983-08-24; source msha-controller-operator-history
- **controller_controls_operator:** Ingram Industries Inc → Ingram Aggregates Inc; 1980-10-08 to 1983-08-24; source msha-controller-operator-history
- **operator_operates_mine:** Vermilion Sand & Gravel Inc → Vermilion Sand & Gravel Incorporated; 1983-08-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dyson Alton → Vermilion Sand & Gravel Incorporated; 1983-08-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dyson Alton → Vermilion Sand & Gravel Inc; 1983-08-25 to current/open; source msha-controller-operator-history