# Relationship history for MSHA mine 2602883

Current hierarchy: **Rick  Joy → Joy Engineering → Chieftain 2200 PID00136CDGL33837**

- 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:** Rick  Joy → Chieftain 2200 PID00136CDGL33837; 2001-10-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Joy Engineering → Chieftain 2200 PID00136CDGL33837; 2022-01-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rick  Joy → Joy Engineering; 2022-01-26 to current/open; source msha-controller-operator-history