# Relationship history for MSHA mine 0404495

Current hierarchy: **Delaware Ventures & L C Hoffman → Blue Range Mining Company L P → Darwin Mines**

- 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:** Atlantic Richfield Company → Darwin Mines; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Anaconda Minerals Company → Darwin Mines; 1981-02-01 to 1984-07-17; source msha-controller-operator-history
- **controller_controls_operator:** Atlantic Richfield Company → Anaconda Minerals Company; 1981-02-01 to 1984-07-17; source msha-controller-operator-history
- **operator_operates_mine:** Qmc Mining Corp → Darwin Mines; 1984-07-18 to 1989-03-19; source msha-controller-operator-history
- **controller_controls_mine:** Robertson Corbin J Jr → Darwin Mines; 1984-07-18 to 1989-03-19; source msha-controller-operator-history
- **controller_controls_operator:** Robertson Corbin J Jr → Qmc Mining Corp; 1984-07-18 to 1989-03-19; source msha-controller-operator-history
- **controller_controls_mine:** Delaware Ventures & L C Hoffman → Darwin Mines; 1986-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Blue Range Mining Company L P → Darwin Mines; 1989-03-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Delaware Ventures & L C Hoffman → Blue Range Mining Company L P; 1989-03-20 to current/open; source msha-controller-operator-history