# Relationship history for MSHA mine 4201532

Current hierarchy: **BHP Billiton → Rio Algom Mining, LLC → RAM LLC - Lisbon 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:** Rio Algom Mining Corp → RAM LLC - Lisbon Mine; 1978-03-09 to 2003-09-22; source msha-controller-operator-history
- **controller_controls_mine:** Rio Algom Ltd → RAM LLC - Lisbon Mine; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rio Algom Ltd → Rio Algom Mining Corp; 1978-03-09 to 2003-09-22; source msha-controller-operator-history
- **controller_controls_mine:** BHP Billiton → RAM LLC - Lisbon Mine; 2002-07-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rio Algom Mining, LLC → RAM LLC - Lisbon Mine; 2003-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BHP Billiton → Rio Algom Mining, LLC; 2003-09-23 to current/open; source msha-controller-operator-history