# Relationship history for MSHA mine 3609401

Current hierarchy: **Blaschak Holding Corp → Blaschak Anthracite Corporation → Primrose Operation**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Blaschak Holding Corp → Primrose Operation; 1981-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blaschak Anthracite Corporation → Primrose Operation; 2006-03-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blaschak Holding Corp → Blaschak Anthracite Corporation; 2006-03-22 to current/open; source msha-controller-operator-history