# Relationship history for MSHA mine 3200150

Current hierarchy: **Knife River Corporation → Strata Corp → Portable Plant #3**

- 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:** Strata Corp → Portable Plant #3; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** James R  Bradshaw et al → Portable Plant #3; 1950-01-01 to 2026-03-22; source msha-controller-operator-history
- **controller_controls_operator:** James R  Bradshaw et al → Strata Corp; 1950-01-01 to 2026-03-22; source msha-controller-operator-history
- **controller_controls_mine:** Knife River Corporation → Portable Plant #3; 2026-03-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Knife River Corporation → Strata Corp; 2026-03-23 to current/open; source msha-controller-operator-history