# Relationship history for MSHA mine 4604602

Current hierarchy: **Shepherd Richard E → Pickens Mining Company → Benbush 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Shepherd Richard E → Benbush No 1 Strip Mine; 1974-12-15 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pickens Mining Company → Benbush No 1 Strip Mine; 1975-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shepherd Richard E → Pickens Mining Company; 1975-04-30 to current/open; source msha-controller-operator-history