# Relationship history for MSHA mine 1202039

Current hierarchy: **Richard L  Sibert → State Line Sand & Gravel Inc → Kolberg-Stedman Crusher #220**

- 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:** Richard L  Sibert → Kolberg-Stedman Crusher #220; 1988-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** State Line Sand & Gravel Inc → Kolberg-Stedman Crusher #220; 1988-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard L  Sibert → State Line Sand & Gravel Inc; 1988-10-01 to current/open; source msha-controller-operator-history