# Relationship history for MSHA mine 3400860

Current hierarchy: **Morgan Ernest & Donna → Morgan Rock & Gravel → Morgans Rock & 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:** Earthmovers General Contractors → Morgans Rock & Gravel; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Earthmovers General Contractors → Morgans Rock & Gravel; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Earthmovers General Contractors → Earthmovers General Contractors; 1950-01-01 to 1979-07-31; source msha-controller-operator-history
- **operator_operates_mine:** El Chaparral Inc → Morgans Rock & Gravel; 1979-08-01 to 1985-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Lewis W H → Morgans Rock & Gravel; 1979-08-01 to 1985-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Lewis W H → El Chaparral Inc; 1979-08-01 to 1985-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Blue Chip Inc → Morgans Rock & Gravel; 1985-04-03 to 1991-06-30; source msha-controller-operator-history
- **controller_controls_mine:** White Charles B → Morgans Rock & Gravel; 1985-04-03 to 1991-06-30; source msha-controller-operator-history
- **controller_controls_operator:** White Charles B → Blue Chip Inc; 1985-04-03 to 1991-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Morgan Rock & Gravel → Morgans Rock & Gravel; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Morgan Ernest & Donna → Morgans Rock & Gravel; 1991-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Morgan Ernest & Donna → Morgan Rock & Gravel; 1991-07-01 to current/open; source msha-controller-operator-history