# Relationship history for MSHA mine 1509365

Current hierarchy: **Young Tollie → Creekview Coal Corp → No 1 Surface**

- 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

- **operator_operates_mine:** Devcol Coal Company Inc → No 1 Surface; 1975-10-01 to 1977-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Hall Cliff → No 1 Surface; 1975-10-01 to 1977-02-28; source msha-controller-operator-history
- **controller_controls_operator:** Hall Cliff → Devcol Coal Company Inc; 1975-10-01 to 1977-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Creekview Coal Corp → No 1 Surface; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Young Tollie → No 1 Surface; 1977-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Young Tollie → Creekview Coal Corp; 1977-03-01 to current/open; source msha-controller-operator-history