# Relationship history for MSHA mine 3607429

Current hierarchy: **Jay W  Shaffer; Dennis L  Shaffer → Shaffer Brothers Coal Company Inc → Berwind 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:** Shaffer Brothers Coal Company Inc → Berwind Mine; 1983-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dennis L  Shaffer et al → Berwind Mine; 1983-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dennis L  Shaffer et al → Shaffer Brothers Coal Company Inc; 1983-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jay W  Shaffer et al → Shaffer Brothers Coal Company Inc; 1983-02-01 to current/open; source msha-controller-operator-history