# Relationship history for MSHA mine 2000668

Current hierarchy: **Fairmount Santrol → Technisand Inc → Bridgman Plant & Pit**

- 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:** Manley Brothers Of Indiana Inc → Bridgman Plant & Pit; 1950-01-01 to 1986-01-27; source msha-controller-operator-history
- **controller_controls_mine:** Russell E  Manley → Bridgman Plant & Pit; 1950-01-01 to 1990-12-26; source msha-controller-operator-history
- **controller_controls_operator:** Russell E  Manley → Manley Brothers Of Indiana Inc; 1950-01-01 to 1986-01-27; source msha-controller-operator-history
- **operator_operates_mine:** Manley Brothers Of Indiana Inc → Bridgman Plant & Pit; 1986-01-28 to 1991-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Hepworth Plc → Bridgman Plant & Pit; 1986-01-28 to 2013-11-30; source msha-controller-operator-history
- **controller_controls_operator:** Hepworth Plc → Manley Brothers Of Indiana Inc; 1986-01-28 to 1991-07-31; source msha-controller-operator-history
- **operator_operates_mine:** Technisand Inc → Bridgman Plant & Pit; 1991-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Fairmount Santrol → Bridgman Plant & Pit; 1991-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Fairmount Santrol → Technisand Inc; 1991-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Paul  Salt → Bridgman Plant & Pit; 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 1991-07-31; source msha-controller-operator-history