# Relationship history for MSHA mine 3600270

Current hierarchy: **James  Adzima → White Rock Silica Sand Company Inc → WHITE ROCK SILICA SAND COMPANY INC.**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **operator_operates_mine:** White Rock Silica Sand Company-Div/Mc Crady Inc → WHITE ROCK SILICA SAND COMPANY INC.; 1950-01-01 to 1990-12-19; source msha-controller-operator-history
- **controller_controls_mine:** W Duff  McCrady → WHITE ROCK SILICA SAND COMPANY INC.; 1950-01-01 to 1990-12-19; source msha-controller-operator-history
- **controller_controls_operator:** W Duff  McCrady → White Rock Silica Sand Company-Div/Mc Crady Inc; 1950-01-01 to 1990-12-19; source msha-controller-operator-history
- **operator_operates_mine:** White Rock Silica Sand Company Inc → WHITE ROCK SILICA SAND COMPANY INC.; 1990-12-20 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James  Adzima → WHITE ROCK SILICA SAND COMPANY INC.; 1990-12-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James  Adzima → White Rock Silica Sand Company Inc; 1990-12-20 to current/open; source msha-controller-operator-history