# Relationship history for MSHA mine 3800644

Current hierarchy: **Tarmac Plc → Tarmac Mid-Atlantic Inc → CENTRAL MAINTENANCE SHOP**

- 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:** Tarmac Plc → CENTRAL MAINTENANCE SHOP; 1988-12-19 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tarmac Mid-Atlantic Inc → CENTRAL MAINTENANCE SHOP; 1990-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tarmac Plc → Tarmac Mid-Atlantic Inc; 1990-01-01 to current/open; source msha-controller-operator-history