# Relationship history for MSHA mine 4101143

Current hierarchy: **Robert Glenn  McClain; Gregory  Angel; Shawn L  Barnes; Gary  Angel → MineralTech Gulf Coast Abrasives, LLC → SWILLEY PIT & 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

- **operator_operates_mine:** Specialty Sand Company → SWILLEY PIT & PLANT; 1950-01-01 to 2022-12-31; source msha-controller-operator-history
- **controller_controls_mine:** W A  Keckley → SWILLEY PIT & PLANT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** W A  Keckley → Specialty Sand Company; 1950-01-01 to 2022-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Robert Glenn  McClain et al → SWILLEY PIT & PLANT; 2017-12-28 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** MineralTech Gulf Coast Abrasives, LLC → SWILLEY PIT & PLANT; 2023-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert Glenn  McClain et al → MineralTech Gulf Coast Abrasives, LLC; 2023-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary  Angel et al → MineralTech Gulf Coast Abrasives, LLC; 2023-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Shawn L  Barnes et al → MineralTech Gulf Coast Abrasives, LLC; 2023-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gregory  Angel et al → MineralTech Gulf Coast Abrasives, LLC; 2023-01-01 to current/open; source msha-controller-operator-history