# Relationship history for MSHA mine 3503257

Current hierarchy: **Briggs Russell & James → Alpine Rock & Redi → ALPINE ROCK LANT**

- 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

- **operator_operates_mine:** Schubert & Sons Ready Mix Llc → ALPINE ROCK LANT; 1986-04-01 to 1997-07-21; source msha-controller-operator-history
- **controller_controls_mine:** Dwaine A  Schubert → ALPINE ROCK LANT; 1986-04-01 to 1997-07-21; source msha-controller-operator-history
- **controller_controls_operator:** Dwaine A  Schubert → Schubert & Sons Ready Mix Llc; 1986-04-01 to 1997-07-21; source msha-controller-operator-history
- **operator_operates_mine:** Alpine Rock & Redi → ALPINE ROCK LANT; 1997-07-22 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Briggs Russell & James → ALPINE ROCK LANT; 1997-07-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Briggs Russell & James → Alpine Rock & Redi; 1997-07-22 to current/open; source msha-controller-operator-history