# Relationship history for MSHA mine 2901864

Current hierarchy: **Douglas E  Hanson → Summit Minerals Inc → Mount Royal**

- 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:** Douglas E  Hanson → Mount Royal; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Summit Minerals Inc → Mount Royal; 1981-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Douglas E  Hanson → Summit Minerals Inc; 1981-05-01 to current/open; source msha-controller-operator-history