# Relationship history for MSHA mine 1601115

Current hierarchy: **T Eric  Johnson → Johnson Gravel Company → JOHNSON 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Em Jay Materials Inc → JOHNSON PIT; 1985-09-01 to 1993-05-24; source msha-controller-operator-history
- **controller_controls_mine:** Johnson Max L → JOHNSON PIT; 1985-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Johnson Max L → Em Jay Materials Inc; 1985-09-01 to 1993-05-24; source msha-controller-operator-history
- **operator_operates_mine:** Johnson Gravel Company → JOHNSON PIT; 1993-05-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** T Eric  Johnson → JOHNSON PIT; 1993-05-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** T Eric  Johnson → Johnson Gravel Company; 1993-05-25 to current/open; source msha-controller-operator-history