# Relationship history for MSHA mine 1600308

Current hierarchy: **Bobby G  Johnson → Industrial Gravel Company Inc → Glen Mora Pit**

- 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

- **operator_operates_mine:** Central Aggregate Company → Glen Mora Pit; 1950-01-01 to 1985-05-29; source msha-controller-operator-history
- **controller_controls_mine:** James L L → Glen Mora Pit; 1950-01-01 to 1985-05-29; source msha-controller-operator-history
- **controller_controls_operator:** James L L → Central Aggregate Company; 1950-01-01 to 1985-05-29; source msha-controller-operator-history
- **controller_controls_mine:** Bobby G  Johnson → Glen Mora Pit; 1981-07-27 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Industrial Gravel Company Inc → Glen Mora Pit; 1985-05-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bobby G  Johnson → Industrial Gravel Company Inc; 1985-05-30 to current/open; source msha-controller-operator-history