# Relationship history for MSHA mine 3609870

Current hierarchy: **Brian L  Balmer → Balmer Flagstone → B & B Quarry**

- 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:** Balmer Flagstone → B & B Quarry; 2010-08-10 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Brian L  Balmer → B & B Quarry; 2010-08-10 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brian L  Balmer → Balmer Flagstone; 2010-08-10 to current/open; source msha-controller-operator-history