# Relationship history for MSHA mine 1401153

Current hierarchy: **Lusk Care Home Inc → Derby Sand Inc → Derby Sand 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:** Derby Sand Inc → Derby Sand Incorporated; 1950-01-01 to 1992-09-23; source msha-controller-operator-history
- **controller_controls_mine:** Lusk Care Home Inc → Derby Sand Incorporated; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lusk Care Home Inc → Derby Sand Inc; 1950-01-01 to 1992-09-23; source msha-controller-operator-history
- **operator_operates_mine:** Burkes Transportation Service Inc → Derby Sand Incorporated; 1992-09-24 to 1994-03-17; source msha-controller-operator-history
- **controller_controls_mine:** Burkes Douglas → Derby Sand Incorporated; 1992-09-24 to 1994-03-17; source msha-controller-operator-history
- **controller_controls_operator:** Burkes Douglas → Burkes Transportation Service Inc; 1992-09-24 to 1994-03-17; source msha-controller-operator-history
- **operator_operates_mine:** Derby Sand Inc → Derby Sand Incorporated; 1994-03-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lusk Care Home Inc → Derby Sand Inc; 1994-03-18 to current/open; source msha-controller-operator-history