# Relationship history for MSHA mine 0202573

Current hierarchy: **Peter Kiewit Sons' Inc → Kiewit Western Company → Portable Crusher 30-1032 Telesmith 3646**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Peter Kiewit Sons' Inc → Portable Crusher 30-1032 Telesmith 3646; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ashland Inc → Portable Crusher 30-1032 Telesmith 3646; 1987-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Tanner Construction → Portable Crusher 30-1032 Telesmith 3646; 1992-04-01 to 1995-07-17; source msha-controller-operator-history
- **controller_controls_operator:** Ashland Inc → Tanner Construction; 1992-04-01 to 1995-07-17; source msha-controller-operator-history
- **operator_operates_mine:** Kiewit Western Company → Portable Crusher 30-1032 Telesmith 3646; 1995-07-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Peter Kiewit Sons' Inc → Kiewit Western Company; 1995-07-18 to current/open; source msha-controller-operator-history