# Relationship history for MSHA mine 4800520

Current hierarchy: **Collie R J → Big Valley View Development Company Inc → Training School Pit**

- 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:** Turner Construction Company → Training School Pit; 1950-01-01 to 1979-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Turner Jack W → Training School Pit; 1950-01-01 to 1979-05-31; source msha-controller-operator-history
- **controller_controls_operator:** Turner Jack W → Turner Construction Company; 1950-01-01 to 1979-04-22; source msha-controller-operator-history
- **operator_operates_mine:** Big Valley View Development Company Inc → Training School Pit; 1979-04-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Collie R J → Training School Pit; 1979-04-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Collie R J → Big Valley View Development Company Inc; 1979-04-23 to current/open; source msha-controller-operator-history