# Relationship history for MSHA mine 4101002

Current hierarchy: **Carmeuse Holding SA → Texas Mining Lp → Voca 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:** Pennsylvania Glass Sand Corp → Voca Plant; 1950-01-01 to 1986-05-14; source msha-controller-operator-history
- **controller_controls_mine:** ITT Corp → Voca Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** ITT Corp → Pennsylvania Glass Sand Corp; 1950-01-01 to 1986-05-14; source msha-controller-operator-history
- **controller_controls_mine:** Rio Tinto Group → Voca Plant; 1986-04-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** U S Silica Company → Voca Plant; 1986-05-15 to 1990-05-07; source msha-controller-operator-history
- **controller_controls_operator:** Rio Tinto Group → U S Silica Company; 1986-05-15 to 1990-05-07; source msha-controller-operator-history
- **operator_operates_mine:** Texas Mining Lp → Voca Plant; 1990-05-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Oglebay Norton Company → Voca Plant; 1990-05-08 to 2008-02-12; source msha-controller-operator-history
- **controller_controls_operator:** Oglebay Norton Company → Texas Mining Lp; 1990-05-08 to 2008-02-12; source msha-controller-operator-history
- **controller_controls_mine:** Carmeuse Holding SA → Voca Plant; 2008-02-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carmeuse Holding SA → Texas Mining Lp; 2008-02-13 to current/open; source msha-controller-operator-history