# Relationship history for MSHA mine 1100050

Current hierarchy: **Martin Marietta Materials Inc → Martin Marietta Aggregates → Hardin County Plant #2**

- 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:** Martin Marietta Materials Inc → Hardin County Plant #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Denny & Simpson Stone Company Inc → Hardin County Plant #2; 1950-01-01 to 1989-10-01; source msha-controller-operator-history
- **controller_controls_mine:** D C  Simpson → Hardin County Plant #2; 1950-01-01 to 1989-10-01; source msha-controller-operator-history
- **controller_controls_operator:** D C  Simpson → Denny & Simpson Stone Company Inc; 1950-01-01 to 1989-10-01; source msha-controller-operator-history
- **operator_operates_mine:** Hardin County Materials Company → Hardin County Plant #2; 1989-10-02 to 1997-05-04; source msha-controller-operator-history
- **controller_controls_mine:** Rigsby & Barnard Quarry Inc  et al → Hardin County Plant #2; 1989-10-02 to 1997-05-04; source msha-controller-operator-history
- **controller_controls_operator:** Rigsby & Barnard Quarry Inc  et al → Hardin County Materials Company; 1989-10-02 to 1997-05-04; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Hardin County Plant #2; 1997-05-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1997-05-05 to current/open; source msha-controller-operator-history