# Relationship history for MSHA mine 4501884

Current hierarchy: **Stevenson Bruce R-Mark E & W D → S D S Lumber Company → S D S Pit**

- 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:** S D S Lumber Company → S D S Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Stevenson Bruce R-Mark E & W D Et Al → S D S Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stevenson Bruce R-Mark E & W D Et Al → S D S Lumber Company; 1950-01-01 to current/open; source msha-controller-operator-history