# Relationship history for MSHA mine 1601021

Current hierarchy: **Herron Carl → Herron Sand & Gravel → Herron Sand And 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:** Bradshaw S & G → Herron Sand And Gravel; 1982-10-01 to 1986-03-26; source msha-controller-operator-history
- **controller_controls_mine:** Bradshaw Jimmy → Herron Sand And Gravel; 1982-10-01 to 1986-03-26; source msha-controller-operator-history
- **controller_controls_operator:** Bradshaw Jimmy → Bradshaw S & G; 1982-10-01 to 1986-03-26; source msha-controller-operator-history
- **operator_operates_mine:** Herron Sand & Gravel → Herron Sand And Gravel; 1986-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Herron Carl → Herron Sand And Gravel; 1986-03-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Herron Carl → Herron Sand & Gravel; 1986-03-27 to current/open; source msha-controller-operator-history