# Relationship history for MSHA mine 2000985

Current hierarchy: **Carmeuse Holding SA → O-N Minerals (Michigan) Company → Carmeuse, Port Inland Operation**

- 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

- **controller_controls_mine:** Minerals Technologies Inc → Carmeuse, Port Inland Operation; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Inland Lime & Stone Company → Carmeuse, Port Inland Operation; 1950-01-01 to 1991-03-06; source msha-controller-operator-history
- **controller_controls_mine:** Inland Steel Industries Inc → Carmeuse, Port Inland Operation; 1950-01-01 to 1991-03-06; source msha-controller-operator-history
- **controller_controls_operator:** Inland Steel Industries Inc → Inland Lime & Stone Company; 1950-01-01 to 1991-03-06; source msha-controller-operator-history
- **operator_operates_mine:** Specialty Minerals Inc → Carmeuse, Port Inland Operation; 1991-03-07 to 1998-04-26; source msha-controller-operator-history
- **controller_controls_operator:** Minerals Technologies Inc → Specialty Minerals Inc; 1991-03-07 to 1998-04-26; source msha-controller-operator-history
- **operator_operates_mine:** O-N Minerals (Michigan) Company → Carmeuse, Port Inland Operation; 1998-04-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Oglebay Norton Company → Carmeuse, Port Inland Operation; 1998-04-27 to 2008-02-12; source msha-controller-operator-history
- **controller_controls_operator:** Oglebay Norton Company → O-N Minerals (Michigan) Company; 1998-04-27 to 2008-02-12; source msha-controller-operator-history
- **controller_controls_mine:** Carmeuse Holding SA → Carmeuse, Port Inland Operation; 2008-02-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carmeuse Holding SA → O-N Minerals (Michigan) Company; 2008-02-13 to current/open; source msha-controller-operator-history