# Relationship history for MSHA mine 0900413

Current hierarchy: **F Browne Gregg Trust → Montgomery Sand Company → Molena Sand 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:** Molena Sand Company Inc → Molena Sand Plant; 1950-01-01 to 1989-10-29; source msha-controller-operator-history
- **controller_controls_mine:** Lawrence J B → Molena Sand Plant; 1950-01-01 to 1989-10-29; source msha-controller-operator-history
- **controller_controls_operator:** Lawrence J B → Molena Sand Company Inc; 1950-01-01 to 1989-10-29; source msha-controller-operator-history
- **controller_controls_mine:** F Browne Gregg Trust → Molena Sand Plant; 1989-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Diamond Sand Company → Molena Sand Plant; 1989-10-30 to 1990-01-04; source msha-controller-operator-history
- **controller_controls_mine:** Rodney H  Greenway → Molena Sand Plant; 1989-10-30 to 2000-07-06; source msha-controller-operator-history
- **controller_controls_operator:** Rodney H  Greenway → Diamond Sand Company; 1989-10-30 to 1990-01-04; source msha-controller-operator-history
- **operator_operates_mine:** Montgomery Sand Company → Molena Sand Plant; 1990-01-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** F Browne Gregg Trust → Montgomery Sand Company; 1990-01-05 to current/open; source msha-controller-operator-history