# Relationship history for MSHA mine 2600445

Current hierarchy: **Eagle Valley Construction Company → Nevada Contractors Inc → Portable Crusher No 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:** Nevada Contractors Inc → Portable Crusher No 1; 1950-01-01 to 1981-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Schwake Mel Jr → Portable Crusher No 1; 1950-01-01 to 1981-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Schwake Mel Jr → Nevada Contractors Inc; 1950-01-01 to 1981-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Nevada Contractors Inc → Portable Crusher No 1; 1981-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Eagle Valley Construction Company → Portable Crusher No 1; 1981-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eagle Valley Construction Company → Nevada Contractors Inc; 1981-07-01 to current/open; source msha-controller-operator-history