# Relationship history for MSHA mine 2200189

Current hierarchy: **Harold P  Hammett Jr → Hammett Gravel Company Inc → Hammett Gravel Company-Yazoo**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Apac-Mississippi Inc → Hammett Gravel Company-Yazoo; 1950-01-01 to 1981-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc → Hammett Gravel Company-Yazoo; 1950-01-01 to 2006-08-27; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc → Apac-Mississippi Inc; 1950-01-01 to 1981-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Heyward C  Green  et al → Hammett Gravel Company-Yazoo; 1950-01-01 to 2019-08-15; source msha-controller-operator-history
- **operator_operates_mine:** Petermann Gravel Inc → Hammett Gravel Company-Yazoo; 1981-07-01 to 1984-02-28; source msha-controller-operator-history
- **controller_controls_mine:** W C  Petermann → Hammett Gravel Company-Yazoo; 1981-07-01 to 1984-02-28; source msha-controller-operator-history
- **controller_controls_operator:** W C  Petermann → Petermann Gravel Inc; 1981-07-01 to 1984-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Hammett Gravel Company Inc → Hammett Gravel Company-Yazoo; 1984-02-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heyward C  Green  et al → Hammett Gravel Company Inc; 1984-02-29 to 2019-08-15; source msha-controller-operator-history
- **controller_controls_operator:** Harold P  Hammett Jr  et al → Hammett Gravel Company Inc; 1984-02-29 to 2019-08-15; source msha-controller-operator-history
- **controller_controls_mine:** CRH PLC → Hammett Gravel Company-Yazoo; 2006-08-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CRH PLC → Apac-Mississippi Inc; 2006-08-28 to 1981-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Harold P  Hammett Jr → Hammett Gravel Company-Yazoo; 2019-08-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold P  Hammett Jr → Hammett Gravel Company Inc; 2019-08-16 to current/open; source msha-controller-operator-history