# Relationship history for MSHA mine 1401812

Current hierarchy: **Scott R  Bergkamp → Bob Bergkamp Construction Co. Inc. → Durler Ranch Quarry**

- 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:** Scott R  Bergkamp → Durler Ranch Quarry; 2002-09-26 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bob Bergkamp Construction Co. Inc. → Durler Ranch Quarry; 2020-03-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Scott R  Bergkamp → Bob Bergkamp Construction Co. Inc.; 2020-03-24 to current/open; source msha-controller-operator-history