# Relationship history for MSHA mine 4800606

Current hierarchy: **Minerals Technologies Inc → American Colloid Company Minerals Group → Crystal Mine**

- 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:** American Colloid Company Minerals Group → Crystal Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Amcol International Corp → Crystal Mine; 1950-01-01 to 2014-07-30; source msha-controller-operator-history
- **controller_controls_operator:** Amcol International Corp → American Colloid Company Minerals Group; 1950-01-01 to 2014-07-30; source msha-controller-operator-history
- **controller_controls_mine:** Minerals Technologies Inc → Crystal Mine; 2014-07-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Minerals Technologies Inc → American Colloid Company Minerals Group; 2014-07-31 to current/open; source msha-controller-operator-history