# Relationship history for MSHA mine 3304725

Current hierarchy: **Collin  Ernst → Ernst Enterprises Inc. → Ernst Enterprises London 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** DC Engineering and Development, LTD. → Ernst Enterprises London Plant; 2016-03-01 to 2020-11-12; source msha-controller-operator-history
- **controller_controls_mine:** Charles W  Duvall et al → Ernst Enterprises London Plant; 2016-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charles W  Duvall et al → DC Engineering and Development, LTD.; 2016-03-01 to 2020-11-12; source msha-controller-operator-history
- **controller_controls_operator:** Jennifer L  Duvall et al → DC Engineering and Development, LTD.; 2016-03-01 to 2020-11-12; source msha-controller-operator-history
- **operator_operates_mine:** Ernst Enterprises Inc. → Ernst Enterprises London Plant; 2020-11-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Ernst → Ernst Enterprises London Plant; 2020-11-13 to 2025-12-18; source msha-controller-operator-history
- **controller_controls_operator:** John  Ernst → Ernst Enterprises Inc.; 2020-11-13 to 2025-12-18; source msha-controller-operator-history
- **controller_controls_mine:** Collin  Ernst → Ernst Enterprises London Plant; 2025-12-19 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Collin  Ernst → Ernst Enterprises Inc.; 2025-12-19 to current/open; source msha-controller-operator-history