# Relationship history for MSHA mine 4503580

Current hierarchy: **Bill M  Pangburn → MATERIAL PROCESSING INC → PORTABLE PLANT**

- 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:** MATERIAL PROCESSING INC → PORTABLE PLANT; 2005-05-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bill M  Pangburn → PORTABLE PLANT; 2005-05-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill M  Pangburn → MATERIAL PROCESSING INC; 2005-05-09 to current/open; source msha-controller-operator-history