# Relationship history for MSHA mine 4500823

Current hierarchy: **Reserve Industries Corp → Reserve Silica Corp → RESERVE SILICA CORPORATION**

- 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:** Industrial Mineral Products Inc → RESERVE SILICA CORPORATION; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **controller_controls_mine:** Industrial Mineral Products Inc → RESERVE SILICA CORPORATION; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Industrial Mineral Products Inc → Industrial Mineral Products Inc; 1950-01-01 to 1986-02-28; source msha-controller-operator-history
- **operator_operates_mine:** Reserve Silica Corp → RESERVE SILICA CORPORATION; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Reserve Industries Corp → RESERVE SILICA CORPORATION; 1986-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Reserve Industries Corp → Reserve Silica Corp; 1986-03-01 to current/open; source msha-controller-operator-history