# Relationship history for MSHA mine 3606777

Current hierarchy: **Fetterolf Group Inc → Fetterolf Mining Sales Company → #1 Plant**

- 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:** Fetterolf Group Inc → #1 Plant; 1978-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Fetterolf Mining Sales Company → #1 Plant; 1979-02-01 to 1979-10-23; source msha-controller-operator-history
- **controller_controls_operator:** Fetterolf Group Inc → Fetterolf Mining Sales Company; 1979-02-01 to 1979-10-23; source msha-controller-operator-history
- **operator_operates_mine:** Fetterolf Mining Sales Company Inc → #1 Plant; 1979-10-24 to 1980-03-09; source msha-controller-operator-history
- **controller_controls_mine:** Walters Harold → #1 Plant; 1979-10-24 to 1980-03-09; source msha-controller-operator-history
- **controller_controls_operator:** Walters Harold → Fetterolf Mining Sales Company Inc; 1979-10-24 to 1980-03-09; source msha-controller-operator-history
- **operator_operates_mine:** Fetterolf Mining Sales Company → #1 Plant; 1980-03-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fetterolf Group Inc → Fetterolf Mining Sales Company; 1980-03-10 to current/open; source msha-controller-operator-history