# Relationship history for MSHA mine 2500919

Current hierarchy: **James D  Schwarck → Schwarck Quarries Inc → Schwarck Quarries (Holmesville Site)**

- 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:** James D  Schwarck → Schwarck Quarries (Holmesville Site); 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Schwarck Quarries Inc → Schwarck Quarries (Holmesville Site); 1979-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James D  Schwarck → Schwarck Quarries Inc; 1979-01-01 to current/open; source msha-controller-operator-history