# Relationship history for MSHA mine 0502398

Current hierarchy: **Fred A  Duckels → Duckels Construction Inc → 1995 Cedarapids Crusher**

- 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:** Bettger Sand & Gravel Company → 1995 Cedarapids Crusher; 1950-01-01 to 1989-08-09; source msha-controller-operator-history
- **controller_controls_mine:** Cecil  Bettger  et al → 1995 Cedarapids Crusher; 1950-01-01 to 1989-08-09; source msha-controller-operator-history
- **controller_controls_operator:** Cecil  Bettger  et al → Bettger Sand & Gravel Company; 1950-01-01 to 1989-08-09; source msha-controller-operator-history
- **controller_controls_mine:** Fred A  Duckels → 1995 Cedarapids Crusher; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Duckels Construction Inc → 1995 Cedarapids Crusher; 1989-08-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fred A  Duckels → Duckels Construction Inc; 1989-08-10 to current/open; source msha-controller-operator-history