# Relationship history for MSHA mine 4100355

Current hierarchy: **Norit NV → Norit Americas Inc → Darco Strip**

- 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:** I C I Americas Inc → Darco Strip; 1950-01-01 to 1985-06-25; source msha-controller-operator-history
- **controller_controls_mine:** Imperial Chemical Industries Ltd → Darco Strip; 1950-01-01 to 1985-06-25; source msha-controller-operator-history
- **controller_controls_operator:** Imperial Chemical Industries Ltd → I C I Americas Inc; 1950-01-01 to 1985-06-25; source msha-controller-operator-history
- **operator_operates_mine:** Norit Americas Inc → Darco Strip; 1985-06-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Norit NV → Darco Strip; 1985-06-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Norit NV → Norit Americas Inc; 1985-06-26 to current/open; source msha-controller-operator-history