# Relationship history for MSHA mine 1301883

Current hierarchy: **Matt H  Walker → L & M Sand & Gravel Inc → #1**

- 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:** L & M Sand & Gravel Inc → #1; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Matt H  Walker → #1; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Matt H  Walker → L & M Sand & Gravel Inc; 1979-01-01 to current/open; source msha-controller-operator-history