# Relationship history for MSHA mine 3303921

Current hierarchy: **Martin Angus → Markel Mining Inc → Dark Diamond**

- 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:** Dark Diamond Coal Corp → Dark Diamond; 1983-01-01 to 1985-10-21; source msha-controller-operator-history
- **controller_controls_mine:** Hunt Stanley O → Dark Diamond; 1983-01-01 to 1985-10-21; source msha-controller-operator-history
- **controller_controls_operator:** Hunt Stanley O → Dark Diamond Coal Corp; 1983-01-01 to 1985-10-21; source msha-controller-operator-history
- **controller_controls_mine:** Martin Angus → Dark Diamond; 1985-07-12 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Markel Mining Inc → Dark Diamond; 1985-10-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Angus → Markel Mining Inc; 1985-10-22 to current/open; source msha-controller-operator-history