# Relationship history for MSHA mine 1513073

Current hierarchy: **Vandagriff Glen Doil → Diamond Fuel Company → No 1 Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Bow Valley Industries Ltd → No 1 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bow Valley Coal Resources Inc → No 1 Mine; 1981-09-01 to 1982-07-26; source msha-controller-operator-history
- **controller_controls_operator:** Bow Valley Industries Ltd → Bow Valley Coal Resources Inc; 1981-09-01 to 1982-07-26; source msha-controller-operator-history
- **operator_operates_mine:** Diamond Fuel Company → No 1 Mine; 1982-07-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Vandagriff Glen Doil → No 1 Mine; 1982-07-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Vandagriff Glen Doil → Diamond Fuel Company; 1982-07-27 to current/open; source msha-controller-operator-history