# Relationship history for MSHA mine 0301405

Current hierarchy: **Smith & Houston Construction Company → Smith & Houston Construction Company → Silas Williams 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:** Smith & Houston Construction Company → Silas Williams Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Smith & Houston Construction Company → Silas Williams Pit; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith & Houston Construction Company → Smith & Houston Construction Company; 1978-03-09 to current/open; source msha-controller-operator-history