# Relationship history for MSHA mine 1700752

Current hierarchy: **Clyde W  Watson; Thomas  Shaffner → Frost Mountain Sand & Gravel LLC → Frost Mountain Sand & Gravel LLC**

- 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:** Frost Mountain Sand & Gravel LLC → Frost Mountain Sand & Gravel LLC; 2003-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Clyde W  Watson  et al → Frost Mountain Sand & Gravel LLC; 2003-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Clyde W  Watson  et al → Frost Mountain Sand & Gravel LLC; 2003-07-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Thomas  Shaffner  et al → Frost Mountain Sand & Gravel LLC; 2003-07-30 to current/open; source msha-controller-operator-history