# Relationship history for MSHA mine 3200409

Current hierarchy: **Nl Industries Inc → N L Baroid-Div/N L Industries Inc → Smith Ullman 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

- **controller_controls_mine:** Nl Industries Inc → Smith Ullman Mine; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Carl J Austad & Son Inc → Smith Ullman Mine; 1950-01-01 to 1980-12-29; source msha-controller-operator-history
- **controller_controls_mine:** Austad J Carleton → Smith Ullman Mine; 1950-01-01 to 1980-12-29; source msha-controller-operator-history
- **controller_controls_operator:** Austad J Carleton → Carl J Austad & Son Inc; 1950-01-01 to 1980-12-29; source msha-controller-operator-history
- **operator_operates_mine:** N L Baroid-Div/N L Industries Inc → Smith Ullman Mine; 1980-12-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nl Industries Inc → N L Baroid-Div/N L Industries Inc; 1980-12-30 to current/open; source msha-controller-operator-history