# Relationship history for MSHA mine 4201580

Current hierarchy: **Thomas Bill → Chemical Mining & Investments Inc → C M I 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:** Chemical Mining & Investments Inc → C M I Mine; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Thomas Bill → C M I Mine; 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas Bill → Chemical Mining & Investments Inc; 1979-01-01 to current/open; source msha-controller-operator-history