# Relationship history for MSHA mine 1202202

Current hierarchy: **The Heritage Group → Speedway Sand & Gravel, Inc. → Columbia City- Plant #4**

- 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:** Mark L  Welker → Columbia City- Plant #4; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** W & W Gravel Company  Inc → Columbia City- Plant #4; 1996-11-01 to 2005-06-02; source msha-controller-operator-history
- **controller_controls_operator:** Mark L  Welker → W & W Gravel Company  Inc; 1996-11-01 to 2005-06-02; source msha-controller-operator-history
- **operator_operates_mine:** Speedway Sand & Gravel, Inc. → Columbia City- Plant #4; 2005-06-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Todd  Fredrick → Columbia City- Plant #4; 2005-06-03 to 2023-05-28; source msha-controller-operator-history
- **controller_controls_operator:** Todd  Fredrick → Speedway Sand & Gravel, Inc.; 2005-06-03 to 2023-05-28; source msha-controller-operator-history
- **controller_controls_mine:** The Heritage Group → Columbia City- Plant #4; 2023-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** The Heritage Group → Speedway Sand & Gravel, Inc.; 2023-05-29 to current/open; source msha-controller-operator-history