# Relationship history for MSHA mine 0100400

Current hierarchy: **Didier-Werke Ag → Didier-Taylor Refractories Corp → Henry County Mines**

- 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:** Wilson Snead Mining Company → Henry County Mines; 1950-01-01 to 1978-11-26; source msha-controller-operator-history
- **controller_controls_mine:** Wilson Snead Mining Company → Henry County Mines; 1950-01-01 to 1978-12-07; source msha-controller-operator-history
- **controller_controls_operator:** Wilson Snead Mining Company → Wilson Snead Mining Company; 1950-01-01 to 1978-11-26; source msha-controller-operator-history
- **operator_operates_mine:** Didier-Taylor Refractories Corp → Henry County Mines; 1978-11-27 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Didier-Werke Ag → Henry County Mines; 1978-11-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Didier-Werke Ag → Didier-Taylor Refractories Corp; 1978-11-27 to current/open; source msha-controller-operator-history