# Relationship history for MSHA mine 4607345

Current hierarchy: **Sidusco Inc → Leckie Smokeless Coal Company → Surface Mine No 20-A**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Sidusco Inc → Surface Mine No 20-A; 1981-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Leckie Smokeless Coal Company → Surface Mine No 20-A; 1987-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sidusco Inc → Leckie Smokeless Coal Company; 1987-08-01 to current/open; source msha-controller-operator-history