# Relationship history for MSHA mine 3607793

Current hierarchy: **Delta Industries Inc → Delta Coal Sales Inc → Delta #8**

- 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:** Delta Industries Inc → Delta #8; 1976-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Delta Coal Sales Inc → Delta #8; 1986-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Delta Industries Inc → Delta Coal Sales Inc; 1986-04-01 to current/open; source msha-controller-operator-history