# Relationship history for MSHA mine 4801497

Current hierarchy: **Tata Chemicals Ltd → Tata Chemicals (Soda Ash) Partners → Tata Chemicals 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

- **controller_controls_mine:** General Chemical  et al → Tata Chemicals Mill; 1989-07-01 to 2008-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Tata Chemicals (Soda Ash) Partners → Tata Chemicals Mill; 1990-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** General Chemical  et al → Tata Chemicals (Soda Ash) Partners; 1990-07-01 to 2008-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Andover Group  et al → Tata Chemicals (Soda Ash) Partners; 1990-07-01 to 2008-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Tata Chemicals Ltd → Tata Chemicals Mill; 2008-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tata Chemicals Ltd → Tata Chemicals (Soda Ash) Partners; 2008-04-01 to current/open; source msha-controller-operator-history