# Relationship history for MSHA mine 2900776

Current hierarchy: **BHP Billiton → Rio Algom Mining LLC → Rio Algom Mining LLC**

- 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 → Rio Algom Mining LLC; 1950-01-01 to 1989-01-16; source msha-controller-operator-history
- **controller_controls_mine:** Kerr-McGee Corp → Rio Algom Mining LLC; 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 → Rio Algom Mining LLC; 1989-01-17 to 2002-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Rio Algom Ltd → Rio Algom Mining LLC; 1989-01-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rio Algom Ltd → Quivira Mining Company; 1989-01-17 to 2002-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Rio Algom Mining LLC → Rio Algom Mining LLC; 2002-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** BHP Billiton → Rio Algom Mining LLC; 2002-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BHP Billiton → Rio Algom Mining LLC; 2002-07-01 to current/open; source msha-controller-operator-history