# Relationship history for MSHA mine 4002042

Current hierarchy: **Smith Robert Excavating Coal Company → Robert Smith Excavating Coal Company → No 2 Surface**

- 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

- **controller_controls_mine:** Smith Robert Excavating Coal Company → No 2 Surface; 1975-01-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Robert Smith Excavating Coal Company → No 2 Surface; 1976-04-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Robert Excavating Coal Company → Robert Smith Excavating Coal Company; 1976-04-16 to current/open; source msha-controller-operator-history