# Relationship history for MSHA mine 2301989

Current hierarchy: **Charles E  Smreker Jr → H Sand & Gravel → H Sand & 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:** Kenney Hulvey Excavating → H Sand & Gravel; 1988-05-01 to 1999-08-23; source msha-controller-operator-history
- **controller_controls_mine:** Kenney  Hulvey → H Sand & Gravel; 1988-05-01 to 1999-08-23; source msha-controller-operator-history
- **controller_controls_operator:** Kenney  Hulvey → Kenney Hulvey Excavating; 1988-05-01 to 1999-08-23; source msha-controller-operator-history
- **operator_operates_mine:** Hirth Excavating Inc → H Sand & Gravel; 1999-08-24 to 2008-07-23; source msha-controller-operator-history
- **controller_controls_mine:** Tony  Hirth → H Sand & Gravel; 1999-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tony  Hirth → Hirth Excavating Inc; 1999-08-24 to 2008-07-23; source msha-controller-operator-history
- **operator_operates_mine:** H Sand & Gravel → H Sand & Gravel; 2008-07-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Charles E  Smreker Jr → H Sand & Gravel; 2008-07-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charles E  Smreker Jr → H Sand & Gravel; 2008-07-24 to current/open; source msha-controller-operator-history