# Relationship history for MSHA mine 2500149

Current hierarchy: **Nebco Inc → Beatrice Sand & Gravel → Boyden Pit & 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:** Consolidated Sand & Gravel Company → Boyden Pit & Plant; 1950-01-01 to 1989-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Jerry E  Meyer → Boyden Pit & Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jerry E  Meyer → Consolidated Sand & Gravel Company; 1950-01-01 to 1989-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Consolidated Sand & Gravel → Boyden Pit & Plant; 1989-04-01 to 2015-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Beatrice Concrete Company Inc → Boyden Pit & Plant; 1989-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Beatrice Concrete Company Inc → Consolidated Sand & Gravel; 1989-04-01 to 2015-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Nebco Inc → Boyden Pit & Plant; 2007-02-13 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Beatrice Sand & Gravel → Boyden Pit & Plant; 2015-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nebco Inc → Beatrice Sand & Gravel; 2015-08-01 to current/open; source msha-controller-operator-history