# Relationship history for MSHA mine 1513522

Current hierarchy: **Mills Willie B & David Gambrell → Morning Glory Coal → Prep 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:** Dundee Fuel Company → Prep Plant; 1982-05-01 to 1985-10-06; source msha-controller-operator-history
- **controller_controls_mine:** Hohmann A F → Prep Plant; 1982-05-01 to 1985-10-06; source msha-controller-operator-history
- **controller_controls_operator:** Hohmann A F → Dundee Fuel Company; 1982-05-01 to 1985-10-06; source msha-controller-operator-history
- **operator_operates_mine:** Morning Glory Coal → Prep Plant; 1985-10-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mills Willie B & David Gambrell → Prep Plant; 1985-10-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mills Willie B & David Gambrell → Morning Glory Coal; 1985-10-07 to current/open; source msha-controller-operator-history