# Relationship history for MSHA mine 3002184

Current hierarchy: **Edward  Herba III → HERBA SAND & GRAVEL → MAYFIELD PIT AND PLANT**

- 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:** Herba Sand & Gravel → MAYFIELD PIT AND PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ed  Herba Jr → MAYFIELD PIT AND PLANT; 1950-01-01 to 2017-03-07; source msha-controller-operator-history
- **controller_controls_operator:** Ed  Herba Jr → Herba Sand & Gravel; 1950-01-01 to 2017-03-07; source msha-controller-operator-history
- **controller_controls_mine:** Edward  Herba III → MAYFIELD PIT AND PLANT; 2017-03-08 to 2022-10-23; source msha-controller-operator-history
- **controller_controls_operator:** Edward  Herba III → Herba Sand & Gravel; 2017-03-08 to 2022-10-23; source msha-controller-operator-history
- **controller_controls_mine:** Susan C Herba → MAYFIELD PIT AND PLANT; 2022-10-24 to 2024-12-05; source msha-controller-operator-history
- **controller_controls_operator:** Susan C Herba → Herba Sand & Gravel; 2022-10-24 to 2024-12-05; source msha-controller-operator-history
- **controller_controls_mine:** Edward  Herba III → MAYFIELD PIT AND PLANT; 2024-12-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward  Herba III → Herba Sand & Gravel; 2024-12-06 to current/open; source msha-controller-operator-history