# Relationship history for MSHA mine 3600797

Current hierarchy: **William E  Corson → Corson Quarries Inc → Bear Gap Stone Division**

- 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:** Bear Gap Stone Inc → Bear Gap Stone Division; 1950-01-01 to 2006-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Edward  Helfrick  et al → Bear Gap Stone Division; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Edward  Helfrick  et al → Bear Gap Stone Inc; 1950-01-01 to 2006-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Kerris  et al → Bear Gap Stone Inc; 1950-01-01 to 2006-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Corson Quarries Inc → Bear Gap Stone Division; 2006-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William E  Corson → Bear Gap Stone Division; 2006-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William E  Corson → Corson Quarries Inc; 2006-05-01 to current/open; source msha-controller-operator-history