# Relationship history for MSHA mine 0202819

Current hierarchy: **Teichert Inc → Western Nevada Materials → Trommel Portable Plant**

- 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:** Old Pueblo Adobe → Trommel Portable Plant; 1999-05-01 to 2017-12-19; source msha-controller-operator-history
- **controller_controls_mine:** Tobert E Barnes et al → Trommel Portable Plant; 1999-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tobert E Barnes et al → Old Pueblo Adobe; 1999-05-01 to 2017-12-19; source msha-controller-operator-history
- **operator_operates_mine:** Western Nevada Materials → Trommel Portable Plant; 2017-12-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Teichert Inc → Trommel Portable Plant; 2017-12-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Teichert Inc → Western Nevada Materials; 2017-12-20 to current/open; source msha-controller-operator-history