# Relationship history for MSHA mine 1401341

Current hierarchy: **Robins John & Joe → Robins Sand & Gravel → Robins Sand & Gravel Pit**

- 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:** Sand Inc → Robins Sand & Gravel Pit; 1979-10-01 to 1981-10-21; source msha-controller-operator-history
- **controller_controls_mine:** Sand Inc → Robins Sand & Gravel Pit; 1979-10-01 to 1981-10-21; source msha-controller-operator-history
- **controller_controls_operator:** Sand Inc → Sand Inc; 1979-10-01 to 1981-10-21; source msha-controller-operator-history
- **operator_operates_mine:** Hi-Plains Sand Inc → Robins Sand & Gravel Pit; 1981-10-22 to 1990-06-20; source msha-controller-operator-history
- **controller_controls_mine:** Robert L  Wacker et al → Robins Sand & Gravel Pit; 1981-10-22 to 2017-11-13; source msha-controller-operator-history
- **controller_controls_operator:** Robert L  Wacker et al → Hi-Plains Sand Inc; 1981-10-22 to 1990-06-20; source msha-controller-operator-history
- **controller_controls_operator:** Gary L  Wacker et al → Hi-Plains Sand Inc; 1981-10-22 to 1990-06-20; source msha-controller-operator-history
- **operator_operates_mine:** Robins Sand & Gravel → Robins Sand & Gravel Pit; 1990-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robins John & Joe → Robins Sand & Gravel Pit; 1990-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robins John & Joe → Robins Sand & Gravel; 1990-06-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Justin C  Wacker et al → Robins Sand & Gravel Pit; 2017-11-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Justin C  Wacker et al → Hi-Plains Sand Inc; 2017-11-14 to 1990-06-20; source msha-controller-operator-history
- **controller_controls_operator:** Todd A  Wacker et al → Hi-Plains Sand Inc; 2017-11-14 to 1990-06-20; source msha-controller-operator-history