# Relationship history for MSHA mine 4608160

Current hierarchy: **Black William E → Ridgeway Development Corp → 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:** Black William E → No 2 Strip; 1991-09-17 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ridgeway Development Corp → No 2 Strip; 1992-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Black William E → Ridgeway Development Corp; 1992-03-01 to current/open; source msha-controller-operator-history