# Relationship history for MSHA mine 2003327

Current hierarchy: **Jack D  Butterfield; William K  Butterfield → Butterfield Yard Service → Butterfield Yard Service**

- 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:** William K  Butterfield  et al → Butterfield Yard Service; 1994-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Butterfield Yard Service → Butterfield Yard Service; 2005-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William K  Butterfield  et al → Butterfield Yard Service; 2005-07-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jack D  Butterfield  et al → Butterfield Yard Service; 2005-07-14 to current/open; source msha-controller-operator-history