# Relationship history for MSHA mine 4402829

Current hierarchy: **USS Holdings Inc → U.S. Silica Company, LLC → Montpelier 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:** Feldspar Corp → Montpelier Plant; 1950-01-01 to 1993-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Zemex Corp → Montpelier Plant; 1950-01-01 to 2003-03-02; source msha-controller-operator-history
- **controller_controls_operator:** Zemex Corp → Feldspar Corp; 1950-01-01 to 1993-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Rio Tinto Group → Montpelier Plant; 1986-04-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** U S Silica Company → Montpelier Plant; 1993-12-01 to 1996-03-08; source msha-controller-operator-history
- **controller_controls_operator:** Rio Tinto Group → U S Silica Company; 1993-12-01 to 1996-03-08; source msha-controller-operator-history
- **operator_operates_mine:** U.S. Silica Company, LLC → Montpelier Plant; 1996-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** USS Holdings Inc → Montpelier Plant; 1996-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USS Holdings Inc → U.S. Silica Company, LLC; 1996-03-09 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cementos Pacasmayo SSA → Montpelier Plant; 2003-03-03 to 2007-09-04; source msha-controller-operator-history
- **controller_controls_operator:** Cementos Pacasmayo SSA → Feldspar Corp; 2003-03-03 to 1993-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → Montpelier Plant; 2007-09-05 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A → Feldspar Corp; 2007-09-05 to 1993-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A  et al → Montpelier Plant; 2011-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A  et al → Feldspar Corp; 2011-04-01 to 1993-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Norsk Mineral AS  et al → Feldspar Corp; 2011-04-01 to 1993-11-30; source msha-controller-operator-history