# Relationship history for MSHA mine 0202423

Current hierarchy: **Cemex S A → Sunward Materials → Plant #79**

- 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

- **controller_controls_mine:** Blue Circle Industries Plc → Plant #79; 1984-05-03 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blue Circle West → Plant #79; 1988-04-01 to 1989-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Blue Circle Industries Plc → Blue Circle West; 1988-04-01 to 1989-07-31; source msha-controller-operator-history
- **operator_operates_mine:** B C W Inc → Plant #79; 1989-08-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Empresas Tolteca → Plant #79; 1989-08-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Empresas Tolteca → B C W Inc; 1989-08-01 to 1990-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Sunward Materials → Plant #79; 1990-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cemex S A → Plant #79; 1990-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cemex S A → Sunward Materials; 1990-10-01 to current/open; source msha-controller-operator-history