# Relationship history for MSHA mine 1301774

Current hierarchy: **Steven R  Gehrke → Gehrke Quarries Inc → Gehrke Quarries Inc**

- 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

- **operator_operates_mine:** Hackney Quarries Inc → Gehrke Quarries Inc; 1950-01-01 to 1987-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Gail  Hackney → Gehrke Quarries Inc; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gail  Hackney → Hackney Quarries Inc; 1950-01-01 to 1987-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Gifford Quarries Inc → Gehrke Quarries Inc; 1987-02-01 to 2000-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Gregg  Reisinger → Gehrke Quarries Inc; 1987-02-01 to 2000-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Gregg  Reisinger → Gifford Quarries Inc; 1987-02-01 to 2000-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Gehrke Quarries Inc → Gehrke Quarries Inc; 2000-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steven R  Gehrke et al → Gehrke Quarries Inc; 2000-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steven R  Gehrke et al → Gehrke Quarries Inc; 2000-07-01 to current/open; source msha-controller-operator-history