# Relationship history for MSHA mine 1600969

Current hierarchy: **Sidney  Amyx → Western Gravel Company Of Jena Inc → WESTERN GRAVEL CO OF JENA INC**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Wallace T  Langston → WESTERN GRAVEL CO OF JENA INC; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Western Gravel Company Inc → WESTERN GRAVEL CO OF JENA INC; 1979-11-01 to 1988-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Wallace T  Langston → Western Gravel Company Inc; 1979-11-01 to 1988-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Western Gravel Company Of Jena Inc → WESTERN GRAVEL CO OF JENA INC; 1989-01-01 to 1992-03-23; source msha-controller-operator-history
- **controller_controls_mine:** Douglas  Robertson → WESTERN GRAVEL CO OF JENA INC; 1989-01-01 to 1992-03-23; source msha-controller-operator-history
- **controller_controls_operator:** Douglas  Robertson → Western Gravel Company Of Jena Inc; 1989-01-01 to 1992-03-23; source msha-controller-operator-history
- **operator_operates_mine:** Western Gravel Company Of Jena Inc → WESTERN GRAVEL CO OF JENA INC; 1992-03-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sidney  Amyx → WESTERN GRAVEL CO OF JENA INC; 1992-03-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Sidney  Amyx → Western Gravel Company Of Jena Inc; 1992-03-24 to current/open; source msha-controller-operator-history