# Relationship history for MSHA mine 0301637

Current hierarchy: **Colas S A → Delta Asphalt Inc → CEDAR RAPIDS PORT PLT**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Delta Asphalt Inc → CEDAR RAPIDS PORT PLT; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Delta Asphalt Inc → CEDAR RAPIDS PORT PLT; 1988-03-01 to 1993-01-28; source msha-controller-operator-history
- **controller_controls_operator:** Delta Asphalt Inc → Delta Asphalt Inc; 1988-03-01 to 1993-01-28; source msha-controller-operator-history
- **operator_operates_mine:** Delta Asphalt Inc → CEDAR RAPIDS PORT PLT; 1993-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Colas S A → CEDAR RAPIDS PORT PLT; 1993-01-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Colas S A → Delta Asphalt Inc; 1993-01-29 to current/open; source msha-controller-operator-history