# Relationship history for MSHA mine 3600809

Current hierarchy: **Black Robert K → Plum Creek Mining Company Inc → Newfield**

- 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:** Bcnr Mining Corp → Newfield; 1950-01-01 to 1985-01-27; source msha-controller-operator-history
- **controller_controls_mine:** Republic Steel Corp → Newfield; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Republic Steel Corp → Bcnr Mining Corp; 1950-01-01 to 1985-01-27; source msha-controller-operator-history
- **operator_operates_mine:** Bcnr Mining Corp → Newfield; 1985-01-28 to 1989-03-16; source msha-controller-operator-history
- **controller_controls_mine:** LTV Corporation → Newfield; 1985-01-28 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** LTV Corporation → Bcnr Mining Corp; 1985-01-28 to 1989-03-16; source msha-controller-operator-history
- **operator_operates_mine:** Penn Hills Energy Inc → Newfield; 1989-03-17 to 1992-09-16; source msha-controller-operator-history
- **controller_controls_mine:** Weiss Alan M → Newfield; 1989-03-17 to 1992-09-16; source msha-controller-operator-history
- **controller_controls_operator:** Weiss Alan M → Penn Hills Energy Inc; 1989-03-17 to 1992-09-16; source msha-controller-operator-history
- **operator_operates_mine:** Plum Creek Mining Company Inc → Newfield; 1992-09-17 to 1993-09-30; source msha-controller-operator-history
- **controller_controls_mine:** Bossick Cynthia B → Newfield; 1992-09-17 to 1993-09-30; source msha-controller-operator-history
- **controller_controls_operator:** Bossick Cynthia B → Plum Creek Mining Company Inc; 1992-09-17 to 1993-09-30; source msha-controller-operator-history
- **operator_operates_mine:** Plum Creek Mining Company Inc → Newfield; 1993-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Black Robert K → Newfield; 1993-10-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Black Robert K → Plum Creek Mining Company Inc; 1993-10-01 to current/open; source msha-controller-operator-history