# Relationship history for MSHA mine 0900091

Current hierarchy: **Imerys S A → Kentucky Tennessee Clay Company → The Feldspar Corporation-Main 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** The Feldspar Corporation → The Feldspar Corporation-Main Plant; 1950-01-01 to 2010-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Zemex Corp → The Feldspar Corporation-Main Plant; 1950-01-01 to 2003-03-02; source msha-controller-operator-history
- **controller_controls_operator:** Zemex Corp → The Feldspar Corporation; 1950-01-01 to 2003-03-02; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → The Feldspar Corporation-Main Plant; 2001-03-28 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Cementos Pacasmayo SSA → The Feldspar Corporation-Main Plant; 2003-03-03 to 2007-09-04; source msha-controller-operator-history
- **controller_controls_operator:** Cementos Pacasmayo SSA → The Feldspar Corporation; 2003-03-03 to 2007-09-04; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A → The Feldspar Corporation-Main Plant; 2007-09-05 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A → The Feldspar Corporation; 2007-09-05 to 2010-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Kentucky Tennessee Clay Company → The Feldspar Corporation-Main Plant; 2011-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A → Kentucky Tennessee Clay Company; 2011-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Imerys S A  et al → The Feldspar Corporation-Main Plant; 2011-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Imerys S A  et al → The Feldspar Corporation; 2011-04-01 to 2010-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Norsk Mineral AS  et al → The Feldspar Corporation; 2011-04-01 to 2010-12-31; source msha-controller-operator-history