# Relationship history for MSHA mine 3901148

Current hierarchy: **Larry Nagel Construction → Larry Nagel Construction → Burtz Pit No 2**

- 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

- **operator_operates_mine:** Larry Nagel Construction → Burtz Pit No 2; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Larry Nagel Construction → Burtz Pit No 2; 1978-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Larry Nagel Construction → Larry Nagel Construction; 1978-03-09 to current/open; source msha-controller-operator-history