# Relationship history for MSHA mine 2003494

Current hierarchy: **Don  Balkema; Mark  Balkema → Balkema Sitework & Development, LLC → Hillside Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Balkema Sitework & Development, LLC → Hillside Gravel; 2014-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Don  Balkema et al → Hillside Gravel; 2014-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don  Balkema et al → Balkema Sitework & Development, LLC; 2014-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mark  Balkema et al → Balkema Sitework & Development, LLC; 2014-07-15 to current/open; source msha-controller-operator-history