# Relationship history for MSHA mine 2400425

Current hierarchy: **Lois L  Smith → L S Ready Mix Concrete → L S READY MIX CONCRETE INC**

- 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:** Carl Robertson Ready Mix → L S READY MIX CONCRETE INC; 1950-01-01 to 1978-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Carl Robertson Ready Mix → L S READY MIX CONCRETE INC; 1950-01-01 to 1978-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Carl Robertson Ready Mix → Carl Robertson Ready Mix; 1950-01-01 to 1978-04-02; source msha-controller-operator-history
- **operator_operates_mine:** L S Ready Mix Concrete → L S READY MIX CONCRETE INC; 1978-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lois L  Smith → L S READY MIX CONCRETE INC; 1978-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lois L  Smith → L S Ready Mix Concrete; 1978-04-03 to current/open; source msha-controller-operator-history