# Relationship history for MSHA mine 1800663

Current hierarchy: **Thomas  Zevely Sr → Campbell Sand & Gravel Company → Cunningham 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:** Thomas  Zevely Sr  et al → Cunningham Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Campbell Sand & Gravel Company → Cunningham Pit; 1978-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas  Zevely Sr  et al → Campbell Sand & Gravel Company; 1978-12-01 to current/open; source msha-controller-operator-history