# Relationship history for MSHA mine 3609837

Current hierarchy: **Michael D  Kovach → Mike Kovach → Dibiase Quarry**

- 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:** Mike Kovach → Dibiase Quarry; 2010-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Michael D  Kovach → Dibiase Quarry; 2010-03-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Michael D  Kovach → Mike Kovach; 2010-03-16 to current/open; source msha-controller-operator-history