# Relationship history for MSHA mine 4102660

Current hierarchy: **Bsi-Western Industries Inc → Hardy Development → Hardy Development Incorporated**

- 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:** United States Gypsum Company → Hardy Development Incorporated; 1950-01-01 to 1988-10-25; source msha-controller-operator-history
- **controller_controls_mine:** USG Corporation → Hardy Development Incorporated; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** USG Corporation → United States Gypsum Company; 1950-01-01 to 1988-10-25; source msha-controller-operator-history
- **operator_operates_mine:** Hardy Development → Hardy Development Incorporated; 1988-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Bsi-Western Industries Inc → Hardy Development Incorporated; 1988-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bsi-Western Industries Inc → Hardy Development; 1988-10-26 to current/open; source msha-controller-operator-history