# Relationship history for MSHA mine 3301600

Current hierarchy: **Walter P Penry → Penry Stone Company → PENRY DREDGE**

- 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

- **operator_operates_mine:** Penry Stone Company → PENRY DREDGE; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Walter P Penry et al → PENRY DREDGE; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Walter P Penry et al → Penry Stone Company; 1950-01-01 to current/open; source msha-controller-operator-history