# Relationship history for MSHA mine 1517060

Current hierarchy: **Adkins Clarence Edward → Zemerex Corp → Zemerex Coal Preparation Plant No1**

- 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:** Northwestern Mining & Processing Company Inc → Zemerex Coal Preparation Plant No1; 1991-04-01 to 1993-08-01; source msha-controller-operator-history
- **controller_controls_mine:** Mare Creek Coal Inc → Zemerex Coal Preparation Plant No1; 1991-04-01 to 1993-08-01; source msha-controller-operator-history
- **controller_controls_operator:** Mare Creek Coal Inc → Northwestern Mining & Processing Company Inc; 1991-04-01 to 1993-08-01; source msha-controller-operator-history
- **operator_operates_mine:** Zemerex Corp → Zemerex Coal Preparation Plant No1; 1993-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Adkins Clarence Edward → Zemerex Coal Preparation Plant No1; 1993-08-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Adkins Clarence Edward → Zemerex Corp; 1993-08-02 to current/open; source msha-controller-operator-history