# Relationship history for MSHA mine 0404202

Current hierarchy: **Strombeck Carl & Chris Nicolos → Rocky Jewel Mine → Rocky Jewel 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Royal Sierra Industries → Rocky Jewel Mine; 1950-01-01 to 1978-05-17; source msha-controller-operator-history
- **controller_controls_mine:** Strombeck Carl & Chris Nicolos → Rocky Jewel Mine; 1950-01-01 to 1978-05-17; source msha-controller-operator-history
- **controller_controls_operator:** Strombeck Carl & Chris Nicolos → Royal Sierra Industries; 1950-01-01 to 1978-05-17; source msha-controller-operator-history
- **operator_operates_mine:** Tionesta Aggregate Company → Rocky Jewel Mine; 1978-05-18 to 1979-02-20; source msha-controller-operator-history
- **controller_controls_mine:** Niilo M  Hyytinen → Rocky Jewel Mine; 1978-05-18 to 1979-02-20; source msha-controller-operator-history
- **controller_controls_operator:** Niilo M  Hyytinen → Tionesta Aggregate Company; 1978-05-18 to 1979-02-20; source msha-controller-operator-history
- **operator_operates_mine:** Rocky Jewel Mine → Rocky Jewel Mine; 1979-02-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Strombeck Carl & Chris Nicolos → Rocky Jewel Mine; 1979-02-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Strombeck Carl & Chris Nicolos → Rocky Jewel Mine; 1979-02-21 to current/open; source msha-controller-operator-history