# Relationship history for MSHA mine 1001943

Current hierarchy: **Steve  Sommer; Lee  Sommer → Canyon Sand & Gravel Inc → CANYON SAND & GRAVEL**

- 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:** Canyon Sand & Gravel Inc → CANYON SAND & GRAVEL; 1998-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Steve  Sommer  et al → CANYON SAND & GRAVEL; 1998-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steve  Sommer  et al → Canyon Sand & Gravel Inc; 1998-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lee  Sommer  et al → Canyon Sand & Gravel Inc; 1998-11-01 to current/open; source msha-controller-operator-history