# Relationship history for MSHA mine 1201909

Current hierarchy: **Heidelberg Materials AG → Heidelberg Materials Midwest Agg, Inc. → Angola Sand & 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

- **controller_controls_mine:** Johnson S E Companies Inc → Angola Sand & Gravel; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Richard Klink Sand & Gravel → Angola Sand & Gravel; 1983-04-01 to 1996-04-15; source msha-controller-operator-history
- **controller_controls_mine:** Richard C  Klink → Angola Sand & Gravel; 1983-04-01 to 1996-04-15; source msha-controller-operator-history
- **controller_controls_operator:** Richard C  Klink → Richard Klink Sand & Gravel; 1983-04-01 to 1996-04-15; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → Angola Sand & Gravel; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Wolcottville Sand & Gravel → Angola Sand & Gravel; 1996-04-16 to 2003-07-12; source msha-controller-operator-history
- **controller_controls_operator:** Johnson S E Companies Inc → Wolcottville Sand & Gravel; 1996-04-16 to 2003-07-12; source msha-controller-operator-history
- **operator_operates_mine:** Heidelberg Materials Midwest Agg, Inc. → Angola Sand & Gravel; 2003-07-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Heidelberg Materials Midwest Agg, Inc.; 2003-07-13 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → Angola Sand & Gravel; 2007-08-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Heidelberg Materials AG → Heidelberg Materials Midwest Agg, Inc.; 2007-08-23 to current/open; source msha-controller-operator-history