# Relationship history for MSHA mine 0901043

Current hierarchy: **F Browne Gregg Trust → Montgomery Sand Company → Kings Bay Sand**

- 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:** Montgomery Sand Company → Kings Bay Sand; 1989-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** F Browne Gregg Trust → Kings Bay Sand; 1989-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** F Browne Gregg Trust → Montgomery Sand Company; 1989-08-01 to current/open; source msha-controller-operator-history