# Relationship history for MSHA mine 0504318

Current hierarchy: **George W  Hall → Hall-Irwin Construction Company → Herbst 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

- **operator_operates_mine:** Hall-Irwin Construction Company → Herbst Pit; 1988-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** George W  Hall et al → Herbst Pit; 1988-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** George W  Hall et al → Hall-Irwin Construction Company; 1988-01-01 to current/open; source msha-controller-operator-history