# Relationship history for MSHA mine 1200703

Current hierarchy: **Paul  Salt → Manley Brothers Of Indiana Inc → Manley Brothers Michigan City 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: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** Martin Marietta Aggregates → Manley Brothers Michigan City Plant; 1950-01-01 to 1983-10-26; source msha-controller-operator-history
- **controller_controls_mine:** Martin Marietta Materials Inc → Manley Brothers Michigan City Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin Marietta Materials Inc → Martin Marietta Aggregates; 1950-01-01 to 1983-10-26; source msha-controller-operator-history
- **controller_controls_mine:** S C R-Sibelco Nv et al → Manley Brothers Michigan City Plant; 1950-01-01 to 2020-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Unimin Corp → Manley Brothers Michigan City Plant; 1983-10-27 to 1986-02-19; source msha-controller-operator-history
- **controller_controls_operator:** S C R-Sibelco Nv et al → Unimin Corp; 1983-10-27 to 1986-02-19; source msha-controller-operator-history
- **controller_controls_mine:** Hepworth Plc → Manley Brothers Michigan City Plant; 1986-01-28 to 2013-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Manley Brothers Of Indiana Inc → Manley Brothers Michigan City Plant; 1986-02-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Hepworth Plc → Manley Brothers Of Indiana Inc; 1986-02-20 to 2013-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Paul  Salt → Manley Brothers Michigan City Plant; 2013-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Paul  Salt → Manley Brothers Of Indiana Inc; 2013-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Covia Holdings LLC → Manley Brothers Michigan City Plant; 2021-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Covia Holdings LLC → Unimin Corp; 2021-01-01 to 1986-02-19; source msha-controller-operator-history