# Relationship history for MSHA mine 0404294

Current hierarchy: **Boral Limited → United States Tile Company → Dominguez Clay Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** United States Tile Company → Dominguez Clay Mine; 1979-04-01 to 1988-11-17; source msha-controller-operator-history
- **controller_controls_mine:** Smith Ralph E Jr → Dominguez Clay Mine; 1979-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith Ralph E Jr → United States Tile Company; 1979-04-01 to 1988-11-17; source msha-controller-operator-history
- **operator_operates_mine:** United States Tile Company → Dominguez Clay Mine; 1988-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Boral Limited → Dominguez Clay Mine; 1988-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Boral Limited → United States Tile Company; 1988-11-18 to current/open; source msha-controller-operator-history