# Relationship history for MSHA mine 2600443

Current hierarchy: **William E  Hintze → Pioneer Materials Inc → Pioneer Materials 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:** Las Vegas Building Materials Inc → Pioneer Materials Incorporated; 1950-01-01 to 1990-06-19; source msha-controller-operator-history
- **controller_controls_mine:** Henderson Phillip T → Pioneer Materials Incorporated; 1950-01-01 to 1990-06-19; source msha-controller-operator-history
- **controller_controls_operator:** Henderson Phillip T → Las Vegas Building Materials Inc; 1950-01-01 to 1990-06-19; source msha-controller-operator-history
- **controller_controls_mine:** William E  Hintze → Pioneer Materials Incorporated; 1989-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Materials Inc → Pioneer Materials Incorporated; 1990-06-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William E  Hintze → Pioneer Materials Inc; 1990-06-20 to current/open; source msha-controller-operator-history