# Relationship history for MSHA mine 3200151

Current hierarchy: **Knife River Corporation → Strata Corporation → Portable Plant  #2**

- 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:** James R  Bradshaw et al → Portable Plant  #2; 1950-01-01 to 2026-03-22; source msha-controller-operator-history
- **operator_operates_mine:** Dusek Sand & Gravel Inc → Portable Plant  #2; 1950-01-01 to 1990-05-28; source msha-controller-operator-history
- **controller_controls_mine:** Ken  Dusek  et al → Portable Plant  #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ken  Dusek  et al → Dusek Sand & Gravel Inc; 1950-01-01 to 1990-05-28; source msha-controller-operator-history
- **controller_controls_operator:** Donald  Dusek  et al → Dusek Sand & Gravel Inc; 1950-01-01 to 1990-05-28; source msha-controller-operator-history
- **operator_operates_mine:** Strata Corporation → Portable Plant  #2; 1990-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James R  Bradshaw et al → Strata Corporation; 1990-05-29 to 2026-03-22; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Portable Plant  #2; 2026-03-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Strata Corporation; 2026-03-23 to current/open; source msha-controller-operator-history