# Relationship history for MSHA mine 0504651

Current hierarchy: **Richard E  Curry → Grand Gravel Company → GRAND 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Richard E  Curry → GRAND GRAVEL; 1983-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Grand Gravel Company → GRAND GRAVEL; 1998-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard E  Curry → Grand Gravel Company; 1998-10-01 to current/open; source msha-controller-operator-history