# Relationship history for MSHA mine 3400834

Current hierarchy: **Heiskill Bobby → Heiskill Gravel Inc → Heiskill Gravel #2**

- 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:** Granite Gravel Company → Heiskill Gravel #2; 1950-01-01 to 1982-11-14; source msha-controller-operator-history
- **controller_controls_mine:** E L  Irwin → Heiskill Gravel #2; 1950-01-01 to 1982-11-14; source msha-controller-operator-history
- **controller_controls_operator:** E L  Irwin → Granite Gravel Company; 1950-01-01 to 1982-11-14; source msha-controller-operator-history
- **controller_controls_mine:** Heiskill Bobby → Heiskill Gravel #2; 1980-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Star Hill Gravel Company Inc → Heiskill Gravel #2; 1982-11-15 to 1989-10-30; source msha-controller-operator-history
- **controller_controls_mine:** Mulliniks Billy J → Heiskill Gravel #2; 1982-11-15 to 1989-10-30; source msha-controller-operator-history
- **controller_controls_operator:** Mulliniks Billy J → Star Hill Gravel Company Inc; 1982-11-15 to 1989-10-30; source msha-controller-operator-history
- **operator_operates_mine:** Heiskill Gravel Inc → Heiskill Gravel #2; 1989-10-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heiskill Bobby → Heiskill Gravel Inc; 1989-10-31 to current/open; source msha-controller-operator-history