# Relationship history for MSHA mine 1200020

Current hierarchy: **Simon A  Davis → Davis Crushed Stone and Lime → John S Davis Inc dba Davis Crushed Stone**

- 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:** Davis Crushed Stone and Lime → John S Davis Inc dba Davis Crushed Stone; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Simon A  Davis → John S Davis Inc dba Davis Crushed Stone; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Simon A  Davis → Davis Crushed Stone and Lime; 1950-01-01 to current/open; source msha-controller-operator-history