# Relationship history for MSHA mine 2901936

Current hierarchy: **Sundt Corp → M M Sundt Construction Company → Sundt Crusher**

- 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:** M M Sundt Construction Company → Sundt Crusher; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sundt Corp → Sundt Crusher; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sundt Corp → M M Sundt Construction Company; 1983-09-01 to current/open; source msha-controller-operator-history