# Relationship history for MSHA mine 0405193

Current hierarchy: **Loring H  Brunius → Sierra Rock → Columbia Portable**

- 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:** Loring H  Brunius → Columbia Portable; 1978-03-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sierra Rock → Columbia Portable; 1992-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Loring H  Brunius → Sierra Rock; 1992-07-01 to current/open; source msha-controller-operator-history