# Relationship history for MSHA mine 0401809

Current hierarchy: **Blatt Gerald R → Star Concrete → SANDMAN 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Hillsdale Rock Company → SANDMAN INC.; 1950-01-01 to 1985-03-12; source msha-controller-operator-history
- **controller_controls_mine:** Henry  Matoza Jr → SANDMAN INC.; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Henry  Matoza Jr → Hillsdale Rock Company; 1950-01-01 to 1985-03-12; source msha-controller-operator-history
- **controller_controls_mine:** Donald R  Claunch → SANDMAN INC.; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Custom Rock Products Inc → SANDMAN INC.; 1985-03-13 to 1986-10-08; source msha-controller-operator-history
- **controller_controls_operator:** Donald R  Claunch → Custom Rock Products Inc; 1985-03-13 to 1986-10-08; source msha-controller-operator-history
- **operator_operates_mine:** Hillsdale Rock Company → SANDMAN INC.; 1986-10-09 to 1987-04-14; source msha-controller-operator-history
- **controller_controls_operator:** Henry  Matoza Jr → Hillsdale Rock Company; 1986-10-09 to 1987-04-14; source msha-controller-operator-history
- **operator_operates_mine:** Star Concrete → SANDMAN INC.; 1987-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Blatt Gerald R → SANDMAN INC.; 1987-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Blatt Gerald R → Star Concrete; 1987-04-15 to current/open; source msha-controller-operator-history