# Relationship history for MSHA mine 3900813

Current hierarchy: **La Mae  Boyden; Jimmy  Boyden → Boyden Construction → Portable Screener (Unit)**

- 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:** Boyden Construction → Portable Screener (Unit); 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Jimmy  Boyden  et al → Portable Screener (Unit); 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jimmy  Boyden  et al → Boyden Construction; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** La Mae  Boyden  et al → Boyden Construction; 1950-01-01 to current/open; source msha-controller-operator-history