# Relationship history for MSHA mine 4703157

Current hierarchy: **Robert M  Shea → WINGRA STONE COMPANY INC. → PLANT #10  SAND CLASSIFIER**

- 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

- **controller_controls_mine:** Robert M  Shea → PLANT #10  SAND CLASSIFIER; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** WINGRA STONE COMPANY INC. → PLANT #10  SAND CLASSIFIER; 1998-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert M  Shea → WINGRA STONE COMPANY INC.; 1998-08-01 to current/open; source msha-controller-operator-history