# Relationship history for MSHA mine 0300400

Current hierarchy: **W Scott  McGeorge → Jeffrey Sand Company → Dredge David H**

- 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:** Jeffrey Sand Company → Dredge David H; 1950-01-01 to 1998-12-27; source msha-controller-operator-history
- **controller_controls_mine:** W D  Jeffrey → Dredge David H; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W D  Jeffrey → Jeffrey Sand Company; 1950-01-01 to 1998-12-27; source msha-controller-operator-history
- **operator_operates_mine:** Jeffrey Sand Company → Dredge David H; 1998-12-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** W Scott  McGeorge et al → Dredge David H; 1998-12-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W Scott  McGeorge et al → Jeffrey Sand Company; 1998-12-28 to current/open; source msha-controller-operator-history