# Relationship history for MSHA mine 3303877

Current hierarchy: **Covia Holdings LLC → Best Sand Corporation → Best Sand Southern**

- 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

- **controller_controls_mine:** S C R-Sibelco Nv et al → Best Sand Southern; 1950-01-01 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Fairmount Santrol → Best Sand Southern; 1950-01-01 to 2018-05-31; source msha-controller-operator-history
- **operator_operates_mine:** Schrader Sand & Gravel → Best Sand Southern; 1981-10-01 to 1994-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Melvin  Schrader → Best Sand Southern; 1981-10-01 to 1994-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Melvin  Schrader → Schrader Sand & Gravel; 1981-10-01 to 1994-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Best Sand Southern → Best Sand Southern; 1994-10-01 to 2009-11-18; source msha-controller-operator-history
- **controller_controls_mine:** Fairmount Santrol → Best Sand Southern; 1994-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fairmount Santrol → Best Sand Southern; 1994-10-01 to 2009-11-18; source msha-controller-operator-history
- **operator_operates_mine:** Best Sand Corporation → Best Sand Southern; 2009-11-19 to 2019-05-28; source msha-controller-operator-history
- **controller_controls_operator:** Fairmount Santrol → Best Sand Corporation; 2009-11-19 to 2018-05-31; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Best Sand Southern; 2018-06-01 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Best Sand Corporation; 2018-06-01 to 2019-05-28; source msha-controller-operator-history
- **operator_operates_mine:** Covia Holdings Corporation → Best Sand Southern; 2019-05-29 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Covia Holdings Corporation; 2019-05-29 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Best Sand Southern; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Best Sand Corporation; 2021-01-01 to 2019-05-28; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Covia Holdings Corporation; 2021-01-01 to 2020-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Best Sand Corporation → Best Sand Southern; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Best Sand Corporation; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Best Sand Corporation; 2021-01-01 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Fairmount Santrol → Best Sand Corporation; 2021-01-01 to 2018-05-31; source msha-controller-operator-history