# Relationship history for MSHA mine 1202238

Current hierarchy: **Jesse  Graber Jr → Frontier Gravel Company Inc → FRONTIER GRAVEL CO. 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:** Frontier Gravel Company Inc → FRONTIER GRAVEL CO. INC.; 1998-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jesse  Graber Jr → FRONTIER GRAVEL CO. INC.; 1998-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jesse  Graber Jr → Frontier Gravel Company Inc; 1998-08-01 to current/open; source msha-controller-operator-history