# Relationship history for MSHA mine 3503323

Current hierarchy: **Humbert W J & Robert W → Humbert Excavating Inc → Spence 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:** Humbert Excavating Inc → Spence Pit; 1988-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Humbert W J & Robert W → Spence Pit; 1988-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Humbert W J & Robert W → Humbert Excavating Inc; 1988-12-01 to current/open; source msha-controller-operator-history