# Relationship history for MSHA mine 4104814

Current hierarchy: **Rusty D  Stevens → WTL Sand and Gravel → Garza Co. Ham 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Rusty D  Stevens → Garza Co. Ham Mine; 2008-02-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** WTL Sand and Gravel → Garza Co. Ham Mine; 2010-04-06 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rusty D  Stevens → WTL Sand and Gravel; 2010-04-06 to current/open; source msha-controller-operator-history