# Relationship history for MSHA mine 0600724

Current hierarchy: **Peter J Koss → Nutmeg Gravel & Excavating Inc → Portable Crusher**

- 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:** Nutmeg Gravel & Excavating Inc → Portable Crusher; 2005-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Peter J Koss → Portable Crusher; 2005-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peter J Koss → Nutmeg Gravel & Excavating Inc; 2005-04-18 to current/open; source msha-controller-operator-history