# Relationship history for MSHA mine 0504132

Current hierarchy: **JLL Partners Incorporated → Pioneer Sand Company Inc → portable screen #157**

- 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:** Robert L  Ryan → portable screen #157; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Gary  Schnurr → portable screen #157; 1950-01-01 to 2014-12-31; source msha-controller-operator-history
- **operator_operates_mine:** C Ryan & Son Inc → portable screen #157; 1986-02-01 to 1990-07-16; source msha-controller-operator-history
- **controller_controls_operator:** Robert L  Ryan → C Ryan & Son Inc; 1986-02-01 to 1990-07-16; source msha-controller-operator-history
- **operator_operates_mine:** Leyden Rock Products Inc → portable screen #157; 1990-07-17 to 1993-11-02; source msha-controller-operator-history
- **controller_controls_mine:** Pan Atlantic Group → portable screen #157; 1990-07-17 to 1993-11-02; source msha-controller-operator-history
- **controller_controls_operator:** Pan Atlantic Group → Leyden Rock Products Inc; 1990-07-17 to 1993-11-02; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Sand Company Inc → portable screen #157; 1993-11-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary  Schnurr → Pioneer Sand Company Inc; 1993-11-03 to 2014-12-31; source msha-controller-operator-history
- **controller_controls_mine:** JLL Partners Incorporated → portable screen #157; 2015-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** JLL Partners Incorporated → Pioneer Sand Company Inc; 2015-01-01 to current/open; source msha-controller-operator-history