# Relationship history for MSHA mine 1200676

Current hierarchy: **John  Schardein → The Sand Trap, Inc → White Sands Mining Co.**

- 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:** M E G Constructors Inc → White Sands Mining Co.; 1950-01-01 to 1985-05-09; source msha-controller-operator-history
- **controller_controls_mine:** C J  Rist → White Sands Mining Co.; 1950-01-01 to 1985-05-09; source msha-controller-operator-history
- **controller_controls_operator:** C J  Rist → M E G Constructors Inc; 1950-01-01 to 1985-05-09; source msha-controller-operator-history
- **operator_operates_mine:** Card Industrial Sand Corp → White Sands Mining Co.; 1985-05-10 to 1989-05-31; source msha-controller-operator-history
- **controller_controls_mine:** William H  Cassady → White Sands Mining Co.; 1985-05-10 to 1989-05-31; source msha-controller-operator-history
- **controller_controls_operator:** William H  Cassady → Card Industrial Sand Corp; 1985-05-10 to 1989-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Rio Tinto Group → White Sands Mining Co.; 1986-04-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** U S Silica Company → White Sands Mining Co.; 1989-06-01 to 1995-04-17; source msha-controller-operator-history
- **controller_controls_operator:** Rio Tinto Group → U S Silica Company; 1989-06-01 to 1995-04-17; source msha-controller-operator-history
- **operator_operates_mine:** The Sand Trap, Inc → White Sands Mining Co.; 1995-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Schardein → White Sands Mining Co.; 1995-04-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Schardein → The Sand Trap, Inc; 1995-04-18 to current/open; source msha-controller-operator-history