# Relationship history for MSHA mine 4702697

Current hierarchy: **Jeffery A  Gaastra → Sam Gaastra & Sons 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

- **operator_operates_mine:** Sam Gaastra & Sons Inc → Portable Plant  #1; 1980-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Sam  Gaastra → Portable Plant  #1; 1980-07-01 to 2021-05-23; source msha-controller-operator-history
- **controller_controls_operator:** Sam  Gaastra → Sam Gaastra & Sons Inc; 1980-07-01 to 2021-05-23; source msha-controller-operator-history
- **controller_controls_mine:** Jeffery A  Gaastra → Portable Plant  #1; 2021-05-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeffery A  Gaastra → Sam Gaastra & Sons Inc; 2021-05-24 to current/open; source msha-controller-operator-history