# Relationship history for MSHA mine 3608637

Current hierarchy: **Thomas  Klinger; Don  Zeigler → F K Z Coal Inc → #1 Slope**

- 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:** Thomas  Klinger et al → #1 Slope; 1997-03-31 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** F K Z Coal Inc → #1 Slope; 1997-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas  Klinger et al → F K Z Coal Inc; 1997-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Don  Zeigler et al → F K Z Coal Inc; 1997-04-01 to current/open; source msha-controller-operator-history