# Relationship history for MSHA mine 1507144

Current hierarchy: **Simpson James W → Skyuka Mining Corp → No 4 Underground**

- 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:** Simpson James W → No 4 Underground; 1973-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Skyuka Mining Corp → No 4 Underground; 1974-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Simpson James W → Skyuka Mining Corp; 1974-06-01 to current/open; source msha-controller-operator-history