# Relationship history for MSHA mine 0501997

Current hierarchy: **Flatiron Paving Company → Flatiron Paving Company → Swartz**

- 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:** Plains Aggregate Company → Swartz; 1950-01-01 to 1978-12-04; source msha-controller-operator-history
- **controller_controls_mine:** Plains Aggregate Company → Swartz; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Plains Aggregate Company → Plains Aggregate Company; 1950-01-01 to 1978-12-04; source msha-controller-operator-history
- **controller_controls_mine:** Flatiron Paving Company → Swartz; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Flatiron Paving Company → Swartz; 1978-12-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Flatiron Paving Company → Flatiron Paving Company; 1978-12-05 to current/open; source msha-controller-operator-history