# Relationship history for MSHA mine 3607293

Current hierarchy: **Bertocci Bart → Appalachian Industries Inc → Ferguson Strip**

- 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:** Appalachian Industries Inc → Ferguson Strip; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bertocci Bart → Ferguson Strip; 1982-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bertocci Bart → Appalachian Industries Inc; 1982-04-01 to current/open; source msha-controller-operator-history