# Relationship history for MSHA mine 4603415

Current hierarchy: **Richard G  Preservati II → Imperial Leasing Inc → Gp #4**

- 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:** United States Steel Mining Company Inc → Gp #4; 1950-01-01 to 1990-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Usx Corp → Gp #4; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Usx Corp → United States Steel Mining Company Inc; 1950-01-01 to 1990-08-14; source msha-controller-operator-history
- **operator_operates_mine:** Imperial Leasing Inc → Gp #4; 1990-08-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Richard G  Preservati II → Gp #4; 1990-08-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard G  Preservati II → Imperial Leasing Inc; 1990-08-15 to current/open; source msha-controller-operator-history