# Relationship history for MSHA mine 3600906

Current hierarchy: **Wheeling Gateway Coal Co & Diamond Gateway Coal Co → Gateway Coal Company → Gateway 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

- **operator_operates_mine:** Gateway Coal Partnership → Gateway Mine; 1950-01-01 to 1980-11-02; source msha-controller-operator-history
- **controller_controls_mine:** LTV Corporation → Gateway Mine; 1950-01-01 to 1980-11-02; source msha-controller-operator-history
- **controller_controls_operator:** LTV Corporation → Gateway Coal Partnership; 1950-01-01 to 1980-11-02; source msha-controller-operator-history
- **operator_operates_mine:** Gateway Coal Company → Gateway Mine; 1980-11-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Wheeling Gateway Coal Co & Diamond Gateway Coal Co → Gateway Mine; 1980-11-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wheeling Gateway Coal Co & Diamond Gateway Coal Co → Gateway Coal Company; 1980-11-03 to current/open; source msha-controller-operator-history