# Relationship history for MSHA mine 3605391

Current hierarchy: **Edward  Helfrich → Kerris & Helfrick Inc → Nelson Bank**

- 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:** Edward  Helfrich et al → Nelson Bank; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** C & F Coal Company → Nelson Bank; 1974-01-01 to 1974-12-30; source msha-controller-operator-history
- **controller_controls_mine:** C & F Coal Co → Nelson Bank; 1974-01-01 to 1974-12-30; source msha-controller-operator-history
- **controller_controls_operator:** C & F Coal Co → C & F Coal Company; 1974-01-01 to 1974-12-30; source msha-controller-operator-history
- **operator_operates_mine:** Kerris & Helfrick Inc → Nelson Bank; 1974-12-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward  Helfrich et al → Kerris & Helfrick Inc; 1974-12-31 to current/open; source msha-controller-operator-history