# Relationship history for MSHA mine 0301607

Current hierarchy: **Covia Holdings LLC → Covia ISP, Inc. → Fort Smith 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Saint-Gobain Proppants → Fort Smith Plant; 1986-04-01 to 2020-11-04; source msha-controller-operator-history
- **controller_controls_mine:** Alcoa Inc & Norton Company → Fort Smith Plant; 1986-04-01 to 2001-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Alcoa Inc & Norton Company → Saint-Gobain Proppants; 1986-04-01 to 2001-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Saint-Gobain → Fort Smith Plant; 2001-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Saint-Gobain → Saint-Gobain Proppants; 2001-04-01 to 2020-11-04; source msha-controller-operator-history
- **operator_operates_mine:** Covia ISP, Inc. → Fort Smith Plant; 2020-11-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Fort Smith Plant; 2020-11-05 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Covia ISP, Inc.; 2020-11-05 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Fort Smith Plant; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Covia ISP, Inc.; 2021-01-01 to current/open; source msha-controller-operator-history