# Relationship history for MSHA mine 3900049

Current hierarchy: **Minerals Technologies Inc → American Colloid Company → BELLE FOURCHE MILL**

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