# Relationship history for MSHA mine 4403223

Current hierarchy: **United  Company → Knox Creek Coal Corp → Hurley Prep 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

- **operator_operates_mine:** Knox Creek Coal Corp → Hurley Prep Plant #1; 1950-01-01 to 1985-09-30; source msha-controller-operator-history
- **controller_controls_mine:** E H  Lester → Hurley Prep Plant #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** E H  Lester → Knox Creek Coal Corp; 1950-01-01 to 1985-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Knox Creek Coal Corp → Hurley Prep Plant #1; 1985-10-01 to 1987-05-10; source msha-controller-operator-history
- **controller_controls_mine:** Cyprus Amax Minerals Company → Hurley Prep Plant #1; 1985-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cyprus Amax Minerals Company → Knox Creek Coal Corp; 1985-10-01 to 1987-05-10; source msha-controller-operator-history
- **controller_controls_mine:** United  Company → Hurley Prep Plant #1; 1987-04-16 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Knox Creek Coal Corp → Hurley Prep Plant #1; 1987-05-11 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** United  Company → Knox Creek Coal Corp; 1987-05-11 to current/open; source msha-controller-operator-history