# Relationship history for MSHA mine 4105347

Current hierarchy: **Fred Weber, Inc. → Iron Mountain Trap Rock → San Marcos Sand and Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Fred Weber, Inc. → San Marcos Sand and Gravel; 1997-11-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Iron Mountain Trap Rock → San Marcos Sand and Gravel; 2018-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fred Weber, Inc. → Iron Mountain Trap Rock; 2018-04-05 to current/open; source msha-controller-operator-history