# Relationship history for MSHA mine 1000318

Current hierarchy: **Covia Holdings LLC → Covia Solutions LLC → Emmett 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

- **controller_controls_mine:** Martin Marietta Materials Inc → Emmett Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Emmett Plant; 1950-01-01 to 2020-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Wedron Silica Division → Emmett Plant; 1950-01-01 to 1979-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Sherman County - KS → Emmett Plant; 1950-01-01 to 1979-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Sherman County - KS → Wedron Silica Division; 1950-01-01 to 1979-04-30; source msha-controller-operator-history
- **operator_operates_mine:** Wedron Silica Company → Emmett Plant; 1979-05-01 to 1979-10-31; source msha-controller-operator-history
- **controller_controls_mine:** Twentieth Century Fox → Emmett Plant; 1979-05-01 to 1979-10-31; source msha-controller-operator-history
- **controller_controls_operator:** Twentieth Century Fox → Wedron Silica Company; 1979-05-01 to 1979-10-31; source msha-controller-operator-history
- **operator_operates_mine:** Martin Marietta Aggregates → Emmett Plant; 1979-11-01 to 1983-10-16; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1979-11-01 to 1983-10-16; source msha-controller-operator-history
- **operator_operates_mine:** Covia Solutions Inc. → Emmett Plant; 1983-10-17 to 2024-07-31; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Covia Solutions Inc.; 1983-10-17 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Emmett Plant; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Covia Solutions Inc.; 2021-01-01 to 2024-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Covia Solutions LLC → Emmett Plant; 2024-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Emmett Plant; 2024-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Covia Solutions LLC; 2024-08-01 to current/open; source msha-controller-operator-history