# Relationship history for MSHA mine 2900541

Current hierarchy: **Rio Algom Ltd → Quivira Mining Company → Ambrosia Lake Mining Operations**

- 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:** Quivira Mining Company → Ambrosia Lake Mining Operations; 1950-01-01 to 1989-01-16; source msha-controller-operator-history
- **controller_controls_mine:** Kerr-McGee Corp → Ambrosia Lake Mining Operations; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kerr-McGee Corp → Quivira Mining Company; 1950-01-01 to 1989-01-16; source msha-controller-operator-history
- **operator_operates_mine:** Quivira Mining Company → Ambrosia Lake Mining Operations; 1989-01-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Rio Algom Ltd → Ambrosia Lake Mining Operations; 1989-01-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rio Algom Ltd → Quivira Mining Company; 1989-01-17 to current/open; source msha-controller-operator-history