# Relationship history for MSHA mine 2103553

Current hierarchy: **Dale A  Sandberg → Sandberg Construction Inc. → Plant #1**

- 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:** Sandberg Construction Inc. → Plant #1; 2006-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Dale A  Sandberg → Plant #1; 2006-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale A  Sandberg → Sandberg Construction Inc.; 2006-10-03 to current/open; source msha-controller-operator-history