# Relationship history for MSHA mine 3608884

Current hierarchy: **Douglas B  Farnham; John V  Pfile → Farnham & Pfile Company, LLP → PBS Coals Shade Ultrasound Plant**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Farnham & Pfile Company, LLP → PBS Coals Shade Ultrasound Plant; 2000-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Douglas B  Farnham et al → PBS Coals Shade Ultrasound Plant; 2000-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Douglas B  Farnham et al → Farnham & Pfile Company, LLP; 2000-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John V  Pfile et al → Farnham & Pfile Company, LLP; 2000-10-01 to current/open; source msha-controller-operator-history