# Relationship history for MSHA mine 3303303

Current hierarchy: **Sterling Coal Company → Sterling Coal Company → Sterling No 2 Strip**

- 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:** Sterling Coal Company → Sterling No 2 Strip; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sterling Coal Company → Sterling No 2 Strip; 1975-04-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sterling Coal Company → Sterling Coal Company; 1975-04-10 to current/open; source msha-controller-operator-history