# Relationship history for MSHA mine 3300148

Current hierarchy: **Jacqueline J  Alf; James P  Jurgensen II; Jason R  Jurgensen → Walls Materials → Walls Materials Plant 1**

- 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:** Shelly & Sands Inc → Walls Materials Plant 1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rockford Stone Company → Walls Materials Plant 1; 1950-01-01 to 1987-01-20; source msha-controller-operator-history
- **controller_controls_mine:** Robert  Beerbower → Walls Materials Plant 1; 1950-01-01 to 1987-01-20; source msha-controller-operator-history
- **controller_controls_operator:** Robert  Beerbower → Rockford Stone Company; 1950-01-01 to 1987-01-20; source msha-controller-operator-history
- **operator_operates_mine:** Western Asphalt Inc → Walls Materials Plant 1; 1987-01-21 to 1987-07-31; source msha-controller-operator-history
- **controller_controls_mine:** Ed L  Muhlenkamp → Walls Materials Plant 1; 1987-01-21 to 1987-07-31; source msha-controller-operator-history
- **controller_controls_operator:** Ed L  Muhlenkamp → Western Asphalt Inc; 1987-01-21 to 1987-07-31; source msha-controller-operator-history
- **operator_operates_mine:** S & S Aggregate → Walls Materials Plant 1; 1987-08-01 to 1992-09-29; source msha-controller-operator-history
- **controller_controls_operator:** Shelly & Sands Inc → S & S Aggregate; 1987-08-01 to 1992-09-29; source msha-controller-operator-history
- **operator_operates_mine:** Walls Materials → Walls Materials Plant 1; 1992-09-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James P  Jurgensen → Walls Materials Plant 1; 1992-09-30 to 2024-10-02; source msha-controller-operator-history
- **controller_controls_operator:** James P  Jurgensen → Walls Materials; 1992-09-30 to 2024-10-02; source msha-controller-operator-history
- **controller_controls_mine:** James P  Jurgensen II et al → Walls Materials Plant 1; 2024-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James P  Jurgensen II et al → Walls Materials; 2024-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jacqueline J  Alf et al → Walls Materials; 2024-10-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jason R  Jurgensen et al → Walls Materials; 2024-10-03 to current/open; source msha-controller-operator-history