# Relationship history for MSHA mine 4500779

Current hierarchy: **Covia Holdings LLC → Unimin Corp → Hamilton Mill**

- 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:** Imc Olivine → Hamilton Mill; 1950-01-01 to 1986-10-31; source msha-controller-operator-history
- **controller_controls_mine:** IMC Global Inc → Hamilton Mill; 1950-01-01 to 1986-11-02; source msha-controller-operator-history
- **controller_controls_operator:** IMC Global Inc → Imc Olivine; 1950-01-01 to 1986-10-31; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Hamilton Mill; 1950-01-01 to 2020-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Aimcor Olivine → Hamilton Mill; 1986-11-01 to 1994-04-28; source msha-controller-operator-history
- **controller_controls_mine:** Charles  Gallagher et al → Hamilton Mill; 1986-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Charles  Gallagher et al → Aimcor Olivine; 1986-11-01 to 1994-04-28; source msha-controller-operator-history
- **operator_operates_mine:** Unimin Corp → Hamilton Mill; 1994-04-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Unimin Corp; 1994-04-29 to 2020-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Hamilton Mill; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Unimin Corp; 2021-01-01 to current/open; source msha-controller-operator-history