# Relationship history for MSHA mine 1800578

Current hierarchy: **John  Duckworth → John Duckworth Coal Company → No 2 Mine Surface**

- 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:** John  Duckworth → No 2 Mine Surface; 1974-12-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** G & B Coal Company → No 2 Mine Surface; 1975-05-01 to 1976-06-22; source msha-controller-operator-history
- **controller_controls_mine:** Green Austin E → No 2 Mine Surface; 1975-05-01 to 1976-06-22; source msha-controller-operator-history
- **controller_controls_operator:** Green Austin E → G & B Coal Company; 1975-05-01 to 1976-06-22; source msha-controller-operator-history
- **operator_operates_mine:** John Duckworth Coal Company → No 2 Mine Surface; 1976-06-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Duckworth → John Duckworth Coal Company; 1976-06-23 to current/open; source msha-controller-operator-history