# Relationship history for MSHA mine 4002237

Current hierarchy: **Barker Jim → Barker Coal Company Inc → Robbins Tipple**

- 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:** Ramsey Timothy T → Robbins Tipple; 1974-12-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Nationwide Inc → Robbins Tipple; 1977-05-01 to 1982-10-25; source msha-controller-operator-history
- **controller_controls_operator:** Ramsey Timothy T → Nationwide Inc; 1977-05-01 to 1982-10-25; source msha-controller-operator-history
- **operator_operates_mine:** Barker Coal Company Inc → Robbins Tipple; 1982-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Barker Jim → Robbins Tipple; 1982-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barker Jim → Barker Coal Company Inc; 1982-10-26 to current/open; source msha-controller-operator-history