# Relationship history for MSHA mine 3503946

Current hierarchy: **David J Dober Jr; David J Dober Sr → Dave Dober Construction Inc → Portable Plant One**

- 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:** Dave Dober Construction Inc → Portable Plant One; 2023-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David J Dober Jr et al → Portable Plant One; 2023-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David J Dober Jr et al → Dave Dober Construction Inc; 2023-04-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David J Dober Sr et al → Dave Dober Construction Inc; 2023-04-13 to current/open; source msha-controller-operator-history