# Relationship history for MSHA mine 1600305

Current hierarchy: **Richard  Richardson → D & J Construction Company Inc → Aimwell Gravel Plant**

- 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:** S A C Materials Inc → Aimwell Gravel Plant; 1950-01-01 to 1985-03-05; source msha-controller-operator-history
- **controller_controls_mine:** Sidney  Amyx → Aimwell Gravel Plant; 1950-01-01 to 1985-03-05; source msha-controller-operator-history
- **controller_controls_operator:** Sidney  Amyx → S A C Materials Inc; 1950-01-01 to 1985-03-05; source msha-controller-operator-history
- **operator_operates_mine:** H H Hanks & Company Inc → Aimwell Gravel Plant; 1985-03-06 to 1989-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Hanks H H → Aimwell Gravel Plant; 1985-03-06 to 1989-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Hanks H H → H H Hanks & Company Inc; 1985-03-06 to 1989-06-30; source msha-controller-operator-history
- **operator_operates_mine:** D & J Construction Company Inc → Aimwell Gravel Plant; 1989-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard  Richardson → Aimwell Gravel Plant; 1989-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard  Richardson → D & J Construction Company Inc; 1989-07-01 to current/open; source msha-controller-operator-history