# Relationship history for MSHA mine 0404741

Current hierarchy: **Calmat Company → Sweetwater Aggregates → Sweetwater Aggregates**

- 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:** Lang Station Sand & Gravel → Sweetwater Aggregates; 1985-05-01 to 1987-05-26; source msha-controller-operator-history
- **controller_controls_mine:** Hoffman E Paul → Sweetwater Aggregates; 1985-05-01 to 1987-05-26; source msha-controller-operator-history
- **controller_controls_operator:** Hoffman E Paul → Lang Station Sand & Gravel; 1985-05-01 to 1987-05-26; source msha-controller-operator-history
- **operator_operates_mine:** Lang Station Inc → Sweetwater Aggregates; 1987-05-27 to 1988-11-22; source msha-controller-operator-history
- **controller_controls_mine:** Lang Richard M → Sweetwater Aggregates; 1987-05-27 to 1988-11-22; source msha-controller-operator-history
- **controller_controls_operator:** Lang Richard M → Lang Station Inc; 1987-05-27 to 1988-11-22; source msha-controller-operator-history
- **operator_operates_mine:** Sweetwater Aggregates → Sweetwater Aggregates; 1988-11-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Calmat Company → Sweetwater Aggregates; 1988-11-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Calmat Company → Sweetwater Aggregates; 1988-11-23 to current/open; source msha-controller-operator-history