# Relationship history for MSHA mine 4702806

Current hierarchy: **Kent C  Johnson → G A Watson Inc → PORTABLE UNIT NO. 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:** G A  Watson → PORTABLE UNIT NO. 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** G A Watson Inc → PORTABLE UNIT NO. 1; 1985-09-01 to 1991-01-01; source msha-controller-operator-history
- **controller_controls_operator:** G A  Watson → G A Watson Inc; 1985-09-01 to 1991-01-01; source msha-controller-operator-history
- **operator_operates_mine:** G A Watson Inc → PORTABLE UNIT NO. 1; 1991-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Kent C  Johnson → PORTABLE UNIT NO. 1; 1991-01-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Kent C  Johnson → G A Watson Inc; 1991-01-02 to current/open; source msha-controller-operator-history