# Relationship history for MSHA mine 3304215

Current hierarchy: **Evergreen Energy Inc → Buckeye Industrial Mining Company → Gavers Prep 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:** Keller Group Inc → Gavers Prep Plant; 1950-01-01 to 2006-04-02; source msha-controller-operator-history
- **operator_operates_mine:** Buckeye Industrial Mining Company → Gavers Prep Plant; 1990-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Keller Group Inc → Buckeye Industrial Mining Company; 1990-09-01 to 2006-04-02; source msha-controller-operator-history
- **controller_controls_mine:** Evergreen Energy Inc → Gavers Prep Plant; 2006-04-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Evergreen Energy Inc → Buckeye Industrial Mining Company; 2006-04-03 to current/open; source msha-controller-operator-history