# Relationship history for MSHA mine 1002046

Current hierarchy: **Tracy M  Twiss; Mel  Harder → Balanced Rock Sand & Gravel Inc → Balanced Rock Sand & Gravel Inc**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Balanced Rock Sand & Gravel Inc → Balanced Rock Sand & Gravel Inc; 2003-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mel  Harder  et al → Balanced Rock Sand & Gravel Inc; 2003-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mel  Harder  et al → Balanced Rock Sand & Gravel Inc; 2003-11-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tracy M  Twiss  et al → Balanced Rock Sand & Gravel Inc; 2003-11-21 to current/open; source msha-controller-operator-history