# Relationship history for MSHA mine 1100247

Current hierarchy: **Bruce E  Schlichting → Schlichting & Sons Excavating, Inc. → Schlichting State Street 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Zaugg'S Bedrock Quarries → Schlichting State Street Quarry; 1979-07-01 to 1981-02-18; source msha-controller-operator-history
- **controller_controls_mine:** Jerry  Zaugg → Schlichting State Street Quarry; 1979-07-01 to 1981-02-18; source msha-controller-operator-history
- **controller_controls_operator:** Jerry  Zaugg → Zaugg'S Bedrock Quarries; 1979-07-01 to 1981-02-18; source msha-controller-operator-history
- **operator_operates_mine:** Schlichting & Sons Excavating, Inc. → Schlichting State Street Quarry; 1981-02-19 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bruce E  Schlichting → Schlichting State Street Quarry; 1981-02-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bruce E  Schlichting → Schlichting & Sons Excavating, Inc.; 1981-02-19 to current/open; source msha-controller-operator-history