# Relationship history for MSHA mine 0200639

Current hierarchy: **David K  Brimhall → Brimhall Sand & Rock & Building Materials → Cottonwood Wash**

- 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:** Brimhall Sand & Rock & Building Materials → Cottonwood Wash; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David K  Brimhall et al → Cottonwood Wash; 2002-06-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David K  Brimhall et al → Brimhall Sand & Rock & Building Materials; 2002-06-05 to current/open; source msha-controller-operator-history