# Relationship history for MSHA mine 4503405

Current hierarchy: **Robert E  Hild → Lake Industries LLC → Menzel Lake 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:** Lake Industries LLC → Menzel Lake Gravel; 1999-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert E  Hild et al → Menzel Lake Gravel; 1999-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert E  Hild et al → Lake Industries LLC; 1999-08-01 to current/open; source msha-controller-operator-history