# Relationship history for MSHA mine 4002039

Current hierarchy: **Davis Bruce D → Tennessee Chemical Company → Iron Roasters**

- 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:** Cities Service Company → Iron Roasters; 1950-01-01 to 1982-10-07; source msha-controller-operator-history
- **controller_controls_mine:** Cities Service Company → Iron Roasters; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cities Service Company → Cities Service Company; 1950-01-01 to 1982-10-07; source msha-controller-operator-history
- **operator_operates_mine:** Tennessee Chemical Company → Iron Roasters; 1982-10-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Davis Bruce D → Iron Roasters; 1982-10-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Davis Bruce D → Tennessee Chemical Company; 1982-10-08 to current/open; source msha-controller-operator-history