# Relationship history for MSHA mine 3605728

Current hierarchy: **Delta Industries Inc → Appalachian Fuels Inc → No 1 Preparation 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Appalachian Fuels Inc → No 1 Preparation Plant; 1975-01-01 to 1980-02-13; source msha-controller-operator-history
- **controller_controls_mine:** Wahl Earl K Jr-David L Jones Et Al → No 1 Preparation Plant; 1975-01-01 to 1980-02-13; source msha-controller-operator-history
- **controller_controls_operator:** Wahl Earl K Jr-David L Jones Et Al → Appalachian Fuels Inc; 1975-01-01 to 1980-02-13; source msha-controller-operator-history
- **operator_operates_mine:** Appalachian Fuels Inc → No 1 Preparation Plant; 1980-02-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Delta Industries Inc → No 1 Preparation Plant; 1980-02-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Delta Industries Inc → Appalachian Fuels Inc; 1980-02-14 to current/open; source msha-controller-operator-history