# Relationship history for MSHA mine 1001801

Current hierarchy: **Martin John B Trust → Silver Still Gypsum → Silver Still Gypsum Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Silver Still Gypsum → Silver Still Gypsum Mine; 1987-07-01 to 1988-04-25; source msha-controller-operator-history
- **controller_controls_mine:** Weston Gerald L → Silver Still Gypsum Mine; 1987-07-01 to 1988-04-25; source msha-controller-operator-history
- **controller_controls_operator:** Weston Gerald L → Silver Still Gypsum; 1987-07-01 to 1988-04-25; source msha-controller-operator-history
- **operator_operates_mine:** Silver Still Gypsum → Silver Still Gypsum Mine; 1988-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Martin John B Trust → Silver Still Gypsum Mine; 1988-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Martin John B Trust → Silver Still Gypsum; 1988-04-26 to current/open; source msha-controller-operator-history