# Relationship history for MSHA mine 4407338

Current hierarchy: **Polycor Inc → POLYCOR VIRGINIA INC. → OLD DOMINION**

- 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

- **controller_controls_mine:** Polycor Inc → OLD DOMINION; 2014-01-23 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Polycor Virginia Inc. → OLD DOMINION; 2015-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Polycor Inc → Polycor Virginia Inc.; 2015-05-01 to current/open; source msha-controller-operator-history