# Relationship history for MSHA mine 3900922

Current hierarchy: **Cynthia A  Monnin → Friessen Construction Company Inc → East-West Pit & 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

- **operator_operates_mine:** Friessen Construction Company Inc → East-West Pit & Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Warren L  Friessen → East-West Pit & Mill; 1950-01-01 to 2024-04-02; source msha-controller-operator-history
- **controller_controls_operator:** Warren L  Friessen → Friessen Construction Company Inc; 1950-01-01 to 2024-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Cynthia A  Monnin → East-West Pit & Mill; 2024-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cynthia A  Monnin → Friessen Construction Company Inc; 2024-04-03 to current/open; source msha-controller-operator-history