# Relationship history for MSHA mine 4000518

Current hierarchy: **Coal Acquisition Inc → Gay Coal Inc → Grays Gap No 2 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Owens Curtis → Grays Gap No 2 Mine; 1950-01-01 to 1977-01-06; source msha-controller-operator-history
- **operator_operates_mine:** T T & W Coal Company → Grays Gap No 2 Mine; 1950-01-01 to 1972-07-12; source msha-controller-operator-history
- **controller_controls_mine:** Thomas Virgil C Et Al → Grays Gap No 2 Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas Virgil C Et Al → T T & W Coal Company; 1950-01-01 to 1972-07-12; source msha-controller-operator-history
- **operator_operates_mine:** Gay Coal Inc → Grays Gap No 2 Mine; 1972-07-13 to 1977-01-06; source msha-controller-operator-history
- **controller_controls_operator:** Owens Curtis → Gay Coal Inc; 1972-07-13 to 1977-01-06; source msha-controller-operator-history
- **operator_operates_mine:** Gay Coal Inc → Grays Gap No 2 Mine; 1977-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Coal Acquisition Inc → Grays Gap No 2 Mine; 1977-01-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Coal Acquisition Inc → Gay Coal Inc; 1977-01-07 to current/open; source msha-controller-operator-history