# Relationship history for MSHA mine 4604249

Current hierarchy: **Voest-Alpine International Corp → Virginia Crews Coal Company → No 6 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:** Massey Energy Company → No 6 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Virginia Crews Coal Company → No 6 Mine; 1974-07-01 to 1978-03-21; source msha-controller-operator-history
- **controller_controls_operator:** Massey Energy Company → Virginia Crews Coal Company; 1974-07-01 to 1978-03-21; source msha-controller-operator-history
- **operator_operates_mine:** Virginia Crews Coal Company → No 6 Mine; 1978-03-22 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Voest-Alpine International Corp → No 6 Mine; 1978-03-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Voest-Alpine International Corp → Virginia Crews Coal Company; 1978-03-22 to current/open; source msha-controller-operator-history