# Relationship history for MSHA mine 0504881

Current hierarchy: **David  Stewart; Travis J Stewart → Western Slope Materials, LLC → Silt 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Silt Sand and Gravel → Silt Plant; 2007-09-04 to 2010-06-16; source msha-controller-operator-history
- **controller_controls_mine:** Wiliam M  Roberts → Silt Plant; 2007-09-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Wiliam M  Roberts → Silt Sand and Gravel; 2007-09-04 to 2010-06-16; source msha-controller-operator-history
- **operator_operates_mine:** Western Slope Materials, LLC → Silt Plant; 2010-06-17 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Travis J  Stewart et al → Silt Plant; 2010-06-17 to 2016-10-04; source msha-controller-operator-history
- **controller_controls_operator:** Travis J  Stewart et al → Western Slope Materials, LLC; 2010-06-17 to 2016-10-04; source msha-controller-operator-history
- **controller_controls_operator:** William M  Roberts et al → Western Slope Materials, LLC; 2010-06-17 to 2016-10-04; source msha-controller-operator-history
- **controller_controls_mine:** Travis J Stewart et al → Silt Plant; 2016-10-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Travis J Stewart et al → Western Slope Materials, LLC; 2016-10-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David  Stewart et al → Western Slope Materials, LLC; 2016-10-05 to current/open; source msha-controller-operator-history