# Relationship history for MSHA mine 0202477

Current hierarchy: **Dale S  Andersen → Canyon Sand Inc → CANYON SAND 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:** Pioneer Materials Inc → CANYON SAND INC; 1989-02-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_mine:** William E  Hintze → CANYON SAND INC; 1989-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William E  Hintze → Pioneer Materials Inc; 1989-02-01 to 1990-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Dale S  Andersen → CANYON SAND INC; 1990-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Abc Redi Mix → CANYON SAND INC; 1990-10-01 to 1991-06-23; source msha-controller-operator-history
- **controller_controls_mine:** Chester  Walkup → CANYON SAND INC; 1990-10-01 to 1991-06-23; source msha-controller-operator-history
- **controller_controls_operator:** Chester  Walkup → Abc Redi Mix; 1990-10-01 to 1991-06-23; source msha-controller-operator-history
- **operator_operates_mine:** Canyon Sand Inc → CANYON SAND INC; 1991-06-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dale S  Andersen → Canyon Sand Inc; 1991-06-24 to current/open; source msha-controller-operator-history