# Relationship history for MSHA mine 1201449

Current hierarchy: **Paul  Bisaillon; Walter  Boughton → Mill Creek Stone & Gravel Corp → Mill Creek Stone & 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:** Mill Creek Stone & Gravel Corp → Mill Creek Stone & Gravel; 1950-01-01 to 1986-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Joseph S  Unger → Mill Creek Stone & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joseph S  Unger → Mill Creek Stone & Gravel Corp; 1950-01-01 to 1986-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Mill Creek Stone & Gravel Corp → Mill Creek Stone & Gravel; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Paul  Bisaillon et al → Mill Creek Stone & Gravel; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul  Bisaillon et al → Mill Creek Stone & Gravel Corp; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walter  Boughton et al → Mill Creek Stone & Gravel Corp; 1986-05-01 to current/open; source msha-controller-operator-history