# Relationship history for MSHA mine 1400506

Current hierarchy: **Christopher J  Eichman → Midwest Concrete Materials, Inc. → KAW Sand 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

- **controller_controls_mine:** Robert H  Eichman → KAW Sand Plant; 1950-01-01 to 2025-01-31; source msha-controller-operator-history
- **operator_operates_mine:** Kewshaw Ready-Mix Concrete & Sand Co Inc → KAW Sand Plant; 1950-01-01 to 1997-03-31; source msha-controller-operator-history
- **controller_controls_mine:** J Daniel  Kershaw → KAW Sand Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** J Daniel  Kershaw → Kewshaw Ready-Mix Concrete & Sand Co Inc; 1950-01-01 to 1997-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Midwest Concrete Materials, Inc. → KAW Sand Plant; 1997-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert H  Eichman → Midwest Concrete Materials, Inc.; 1997-04-01 to 2025-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Christopher J  Eichman → KAW Sand Plant; 2025-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christopher J  Eichman → Midwest Concrete Materials, Inc.; 2025-02-01 to current/open; source msha-controller-operator-history