# Relationship history for MSHA mine 3003654

Current hierarchy: **William J  Hammersmith → WILLIAM J. HAMMERSMITH QUALITY CONSTRUCTION → HAMMERSMITH GRAVEL MINE**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** William J. Hammersmith Quality Construction → HAMMERSMITH GRAVEL MINE; 2008-11-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William J  Hammersmith → HAMMERSMITH GRAVEL MINE; 2008-11-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William J  Hammersmith → William J. Hammersmith Quality Construction; 2008-11-12 to current/open; source msha-controller-operator-history