# Relationship history for MSHA mine 2002977

Current hierarchy: **Robert J  Dean → Great Lakes Gravel Company Inc → GREAT LAKES 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:** Great Lakes Gravel Company Inc → GREAT LAKES GRAVEL CO. INC.; 1996-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert J  Dean → GREAT LAKES GRAVEL CO. INC.; 1996-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert J  Dean → Great Lakes Gravel Company Inc; 1996-05-01 to current/open; source msha-controller-operator-history