# Relationship history for MSHA mine 4201848

Current hierarchy: **Peter Kiewit Sons' Inc → Kiewit Western Company → Portable Crusher #2**

- 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:** Peter Kiewit Sons' Inc → Portable Crusher #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kiewit Western Company → Portable Crusher #2; 1983-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peter Kiewit Sons' Inc → Kiewit Western Company; 1983-09-01 to current/open; source msha-controller-operator-history