# Relationship history for MSHA mine 4607570

Current hierarchy: **Booth Mary Ann → Mary Lynn Inc → Prep Plant**

- 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:** G A R Mining → Prep Plant; 1988-09-01 to 1989-06-09; source msha-controller-operator-history
- **controller_controls_mine:** Cobb William W → Prep Plant; 1988-09-01 to 1989-06-09; source msha-controller-operator-history
- **controller_controls_operator:** Cobb William W → G A R Mining; 1988-09-01 to 1989-06-09; source msha-controller-operator-history
- **operator_operates_mine:** Mary Lynn Inc → Prep Plant; 1989-06-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Booth Mary Ann → Prep Plant; 1989-06-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Booth Mary Ann → Mary Lynn Inc; 1989-06-10 to current/open; source msha-controller-operator-history