# Relationship history for MSHA mine 1508593

Current hierarchy: **Powell Thomas H → Powell Mining Company → Powell Mining Co No 1 Strip Mine**

- 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

- **operator_operates_mine:** Powell Mining Company → Powell Mining Co No 1 Strip Mine; 1975-07-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Powell Thomas H → Powell Mining Co No 1 Strip Mine; 1975-07-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Powell Thomas H → Powell Mining Company; 1975-07-25 to current/open; source msha-controller-operator-history