# Relationship history for MSHA mine 3606244

Current hierarchy: **Smith Darvin C--Allen R Kramer → K & S Coal Company → K & S Stripping**

- 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:** Smith Darvin C--Allen R Kramer Et Al → K & S Stripping; 1974-04-19 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** K & S Coal Company → K & S Stripping; 1976-10-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Darvin C--Allen R Kramer Et Al → K & S Coal Company; 1976-10-21 to current/open; source msha-controller-operator-history