# Relationship history for MSHA mine 1102900

Current hierarchy: **Bruce E  Schlichting → Schlichting & Sons Excavating Inc → Portable Plant #1**

- 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:** Bruce E  Schlichting → Portable Plant #1; 1981-02-19 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Schlichting & Sons Excavating Inc → Portable Plant #1; 1990-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bruce E  Schlichting → Schlichting & Sons Excavating Inc; 1990-08-01 to current/open; source msha-controller-operator-history