# Relationship history for MSHA mine 2901267

Current hierarchy: **Chevron Corporation → Chevron Mining Inc → Questa Mine & 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:** Chevron Corporation → Questa Mine & Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Molycorp Inc → Questa Mine & Mill; 1950-01-01 to 2007-08-31; source msha-controller-operator-history
- **controller_controls_mine:** Unocal Corp → Questa Mine & Mill; 1950-01-01 to 2005-11-29; source msha-controller-operator-history
- **controller_controls_operator:** Unocal Corp → Molycorp Inc; 1950-01-01 to 2005-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Chevron Corporation → Questa Mine & Mill; 2005-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chevron Corporation → Molycorp Inc; 2005-11-30 to 2007-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Chevron Mining Inc → Questa Mine & Mill; 2007-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chevron Corporation → Chevron Mining Inc; 2007-09-01 to current/open; source msha-controller-operator-history