# Relationship history for MSHA mine 3102012

Current hierarchy: **S C R-Sibelco Nv → Sibelco North America, Inc. → Crystal 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

- **controller_controls_mine:** Zemex Corp → Crystal Plant; 1950-01-01 to 2003-03-02; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Crystal Plant; 1950-01-01 to 2020-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Feldspar Corp → Crystal Plant; 1987-10-01 to 1991-05-08; source msha-controller-operator-history
- **controller_controls_operator:** Zemex Corp → Feldspar Corp; 1987-10-01 to 1991-05-08; source msha-controller-operator-history
- **operator_operates_mine:** Unimin Corp → Crystal Plant; 1991-05-09 to 2018-05-31; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Unimin Corp; 1991-05-09 to 2018-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Cementos Pacasmayo SSA → Crystal 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 1991-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → Crystal 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 1991-05-08; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A  et al → Crystal 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 1991-05-08; source msha-controller-operator-history
- **controller_controls_operator:** Norsk Mineral AS  et al → Feldspar Corp; 2011-04-01 to 1991-05-08; source msha-controller-operator-history
- **operator_operates_mine:** Sibelco North America, Inc. → Crystal Plant; 2018-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Crystal Plant; 2018-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Sibelco North America, Inc.; 2018-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Crystal Plant; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Unimin Corp; 2021-01-01 to 2018-05-31; source msha-controller-operator-history