# Relationship history for MSHA mine 0504541

Current hierarchy: **JLL Partners Incorporated → Pioneer Sand Company → Power Screen Unit 18170**

- 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:** Gary  Schnurr → Power Screen Unit 18170; 1950-01-01 to 2014-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Sand Company → Power Screen Unit 18170; 1994-02-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary  Schnurr → Pioneer Sand Company; 1994-02-01 to 2014-12-31; source msha-controller-operator-history
- **controller_controls_mine:** JLL Partners Incorporated → Power Screen Unit 18170; 2015-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** JLL Partners Incorporated → Pioneer Sand Company; 2015-01-01 to current/open; source msha-controller-operator-history