# Relationship history for MSHA mine 1302162

Current hierarchy: **Bill  Boyer → Boyer Ready Mix Sand & Rock Inc → Portable Plant #1**

- 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

- **controller_controls_mine:** Bill  Boyer → Portable Plant #1; 1987-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Boyer Ready Mix Sand & Rock Inc → Portable Plant #1; 1988-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bill  Boyer → Boyer Ready Mix Sand & Rock Inc; 1988-11-01 to current/open; source msha-controller-operator-history