# Relationship history for MSHA mine 2600816

Current hierarchy: **Imerys S A → Imerys Filtration Minerals Inc → Fernley 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:** Cyprus Diatomite Company → Fernley Plant; 1950-01-01 to 1980-09-21; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Mines Corp → Fernley Plant; 1950-01-01 to 1980-09-21; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Mines Corp → Cyprus Diatomite Company; 1950-01-01 to 1980-09-21; source msha-controller-operator-history
- **operator_operates_mine:** Cyprus Mines Corp → Fernley Plant; 1980-09-22 to 1987-11-08; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Amax Minerals Company → Fernley Plant; 1980-09-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Amax Minerals Company → Cyprus Mines Corp; 1980-09-22 to 1987-11-08; source msha-controller-operator-history
- **operator_operates_mine:** Cr Minerals Corp → Fernley Plant; 1987-11-09 to 1998-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Canyon Resources Corp → Fernley Plant; 1987-11-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Canyon Resources Corp → Cr Minerals Corp; 1987-11-09 to 1998-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Alleghany Corp → Fernley Plant; 1991-07-26 to 2005-07-14; source msha-controller-operator-history
- **operator_operates_mine:** Cr Minerals Company Llc → Fernley Plant; 1999-01-01 to 2001-04-19; source msha-controller-operator-history
- **controller_controls_mine:** CR Minerals Company LLC → Fernley Plant; 1999-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** CR Minerals Company LLC → Cr Minerals Company Llc; 1999-01-01 to 2001-04-19; source msha-controller-operator-history
- **operator_operates_mine:** Imerys Filtration Minerals Inc → Fernley Plant; 2001-04-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alleghany Corp → Imerys Filtration Minerals Inc; 2001-04-20 to 2005-07-14; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → Fernley Plant; 2005-07-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A → Imerys Filtration Minerals Inc; 2005-07-15 to current/open; source msha-controller-operator-history