# Relationship history for MSHA mine 1512905

Current hierarchy: **Heidelberg Materials AG → HEIDELBERG MATERIALS MIDWEST AGG, INC. → LAUREL QUARRY**

- 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:** Elmo Greer & Sons Inc → LAUREL QUARRY; 1981-06-01 to 1997-02-02; source msha-controller-operator-history
- **controller_controls_mine:** Rex  Greer → LAUREL QUARRY; 1981-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rex  Greer → Elmo Greer & Sons Inc; 1981-06-01 to 1997-02-02; source msha-controller-operator-history
- **controller_controls_mine:** Hanson PLC → LAUREL QUARRY; 1988-11-14 to 2007-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Heidelberg Materials Midwest Agg, Inc. → LAUREL QUARRY; 1997-02-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hanson PLC → Heidelberg Materials Midwest Agg, Inc.; 1997-02-03 to 2007-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Heidelberg Materials AG → LAUREL QUARRY; 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