# Relationship history for MSHA mine 3401083

Current hierarchy: **Regan Roger--Kenneth Porter & W A Goodwin → Crystal Coal Company → Crystal Coal Strip**

- 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

- **operator_operates_mine:** Crystal Coal Company → Crystal Coal Strip; 1978-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Regan Roger--Kenneth Porter & W A Goodwin → Crystal Coal Strip; 1978-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Regan Roger--Kenneth Porter & W A Goodwin → Crystal Coal Company; 1978-03-01 to current/open; source msha-controller-operator-history