# Relationship history for MSHA mine 4102339

Current hierarchy: **Travis Delbert  Walker → Walker Sand Inc → Walkers 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

- **controller_controls_mine:** Travis Delbert  Walker → Walkers Sand Incorporated; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Sand Services Inc → Walkers Sand Incorporated; 1950-01-01 to 1989-03-01; source msha-controller-operator-history
- **controller_controls_mine:** Praisewater Harry & Walter Paschall → Walkers Sand Incorporated; 1950-01-01 to 1989-03-01; source msha-controller-operator-history
- **controller_controls_operator:** Praisewater Harry & Walter Paschall → Sand Services Inc; 1950-01-01 to 1989-03-01; source msha-controller-operator-history
- **operator_operates_mine:** Walker Sand Inc → Walkers Sand Incorporated; 1989-03-02 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Travis Delbert  Walker → Walker Sand Inc; 1989-03-02 to current/open; source msha-controller-operator-history