# Relationship history for MSHA mine 1509541

Current hierarchy: **Pargas Inc → River Processing Inc → No 9 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

- **controller_controls_mine:** Pargas Inc → No 9 Mine; 1973-03-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** River Processing Inc → No 9 Mine; 1976-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pargas Inc → River Processing Inc; 1976-03-01 to current/open; source msha-controller-operator-history