# Relationship history for MSHA mine 3304155

Current hierarchy: **CSR Ltd → American Aggregates Corp → Ernst Materials Service Inc**

- 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

- **operator_operates_mine:** Ernst Materials Service Inc → Ernst Materials Service Inc; 1989-03-01 to 1990-03-18; source msha-controller-operator-history
- **controller_controls_mine:** John  Ernst → Ernst Materials Service Inc; 1989-03-01 to 1990-03-18; source msha-controller-operator-history
- **controller_controls_operator:** John  Ernst → Ernst Materials Service Inc; 1989-03-01 to 1990-03-18; source msha-controller-operator-history
- **controller_controls_mine:** CSR Ltd → Ernst Materials Service Inc; 1990-02-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** American Aggregates Corp → Ernst Materials Service Inc; 1990-03-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CSR Ltd → American Aggregates Corp; 1990-03-19 to current/open; source msha-controller-operator-history