# Relationship history for MSHA mine 0102093

Current hierarchy: **William G  Yates Jr → Baldwin Sand & Gravel → BALDWIN SAND & GRAVEL - PIT #4**

- 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

- **controller_controls_mine:** Baldwin Bob → BALDWIN SAND & GRAVEL - PIT #4; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Baldwin Sand & Gravel Company → BALDWIN SAND & GRAVEL - PIT #4; 1979-01-01 to 1981-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Baldwin Bob → Baldwin Sand & Gravel Company; 1979-01-01 to 1981-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Baldwin Sand & Gravel → BALDWIN SAND & GRAVEL - PIT #4; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William G  Yates Jr et al → BALDWIN SAND & GRAVEL - PIT #4; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William G  Yates Jr et al → Baldwin Sand & Gravel; 1981-04-01 to current/open; source msha-controller-operator-history