# Relationship history for MSHA mine 1800660

Current hierarchy: **Fetterolf Group Inc → Fetterolf Mining Inc → Fetterolf #1**

- 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:** Wilhelm Gilbert → Fetterolf #1; 1977-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Fetterolf Group Inc → Fetterolf #1; 1977-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Wilhelm Coal Inc → Fetterolf #1; 1978-06-01 to 1978-07-26; source msha-controller-operator-history
- **controller_controls_operator:** Wilhelm Gilbert → Wilhelm Coal Inc; 1978-06-01 to 1978-07-26; source msha-controller-operator-history
- **operator_operates_mine:** Fetterolf Mining Inc → Fetterolf #1; 1978-07-27 to 1979-05-22; source msha-controller-operator-history
- **controller_controls_operator:** Fetterolf Group Inc → Fetterolf Mining Inc; 1978-07-27 to 1979-05-22; source msha-controller-operator-history
- **operator_operates_mine:** Frank Gerney Coal Company → Fetterolf #1; 1979-05-23 to 1980-09-01; source msha-controller-operator-history
- **controller_controls_mine:** Gerney Frank → Fetterolf #1; 1979-05-23 to 1980-09-01; source msha-controller-operator-history
- **controller_controls_operator:** Gerney Frank → Frank Gerney Coal Company; 1979-05-23 to 1980-09-01; source msha-controller-operator-history
- **operator_operates_mine:** Fetterolf Mining Inc → Fetterolf #1; 1980-09-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fetterolf Group Inc → Fetterolf Mining Inc; 1980-09-02 to current/open; source msha-controller-operator-history