# Relationship history for MSHA mine 4300477

Current hierarchy: **Richard A  Bisson → Bisson Gravel Products → Bisson Gravel Products**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Palmer Earth Products → Bisson Gravel Products; 1992-07-01 to 1997-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Priscilla  Palmer → Bisson Gravel Products; 1992-07-01 to 1997-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Priscilla  Palmer → Palmer Earth Products; 1992-07-01 to 1997-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Bisson Excavating → Bisson Gravel Products; 1997-06-01 to 2004-06-20; source msha-controller-operator-history
- **controller_controls_mine:** Richard  Bisson → Bisson Gravel Products; 1997-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard  Bisson → Bisson Excavating; 1997-06-01 to 2004-06-20; source msha-controller-operator-history
- **operator_operates_mine:** Bisson Gravel Products → Bisson Gravel Products; 2004-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard A  Bisson → Bisson Gravel Products; 2004-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard A  Bisson → Bisson Gravel Products; 2004-06-21 to current/open; source msha-controller-operator-history