# Relationship history for MSHA mine 4300305

Current hierarchy: **John H  Gross → John H Gross → Northfield Pit**

- 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

- **controller_controls_mine:** John H  Gross → Northfield Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** John H Gross → Northfield Pit; 1978-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John H  Gross → John H Gross; 1978-11-01 to current/open; source msha-controller-operator-history