# Relationship history for MSHA mine 3609934

Current hierarchy: **Robert R  Stremick → Robert R. Stremick Trucking → Kaska Operation**

- 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:** Bernard J  Kuperavage Jr et al → Kaska Operation; 2009-04-30 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** K K Coal LLC → Kaska Operation; 2011-07-07 to 2013-06-06; source msha-controller-operator-history
- **controller_controls_operator:** Bernard J  Kuperavage Jr et al → K K Coal LLC; 2011-07-07 to 2013-06-06; source msha-controller-operator-history
- **operator_operates_mine:** Robert R. Stremick Trucking → Kaska Operation; 2013-06-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert R  Stremick → Kaska Operation; 2013-06-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert R  Stremick → Robert R. Stremick Trucking; 2013-06-07 to current/open; source msha-controller-operator-history