# Relationship history for MSHA mine 1400555

Current hierarchy: **Christopher J  Eichman → Midwest Concrete Materials → Wabaunsee County 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

- **operator_operates_mine:** Midwest Concrete Materials → Wabaunsee County Sand Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert H  Eichman → Wabaunsee County Sand Plant; 1950-01-01 to 2025-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Robert H  Eichman → Midwest Concrete Materials; 1950-01-01 to 2025-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Christopher J  Eichman → Wabaunsee County Sand Plant; 2025-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christopher J  Eichman → Midwest Concrete Materials; 2025-02-01 to current/open; source msha-controller-operator-history