# Relationship history for MSHA mine 4703685

Current hierarchy: **Randy  Spangler; Nancy  Hemker → Cameron Rail Site LLC → Sand Plant**

- 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:** Cameron Rail Site LLC → Sand Plant; 2013-08-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Hemker et al → Sand Plant; 2013-08-13 to 2016-06-25; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Hemker et al → Cameron Rail Site LLC; 2013-08-13 to 2016-06-25; source msha-controller-operator-history
- **controller_controls_operator:** Randy  Spangler et al → Cameron Rail Site LLC; 2013-08-13 to 2016-06-25; source msha-controller-operator-history
- **controller_controls_mine:** Randy  Spangler et al → Sand Plant; 2016-06-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Randy  Spangler et al → Cameron Rail Site LLC; 2016-06-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nancy  Hemker et al → Cameron Rail Site LLC; 2016-06-26 to current/open; source msha-controller-operator-history