# Relationship history for MSHA mine 4002937

Current hierarchy: **USS Holdings Inc → U.S.Silica Company, LLC → Jackson 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:** Nicks Silica Company Inc → Jackson Plant; 1986-09-01 to 1998-01-16; source msha-controller-operator-history
- **controller_controls_mine:** W A  Nicks → Jackson Plant; 1986-09-01 to 1998-01-16; source msha-controller-operator-history
- **controller_controls_operator:** W A  Nicks → Nicks Silica Company Inc; 1986-09-01 to 1998-01-16; source msha-controller-operator-history
- **controller_controls_mine:** USS Holdings Inc → Jackson Plant; 1996-03-09 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** U.S.Silica Company, LLC → Jackson Plant; 1998-01-17 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USS Holdings Inc → U.S.Silica Company, LLC; 1998-01-17 to current/open; source msha-controller-operator-history