# Relationship history for MSHA mine 0300911

Current hierarchy: **David D.  Duffield; Luke B.  Duffield → Duffield Holdings, LLP → Duffield Holdings Materials**

- 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:** Robinson Inc → Duffield Holdings Materials; 1950-01-01 to 2009-11-30; source msha-controller-operator-history
- **controller_controls_mine:** Robby R  Robinson → Duffield Holdings Materials; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robby R  Robinson → Robinson Inc; 1950-01-01 to 2009-11-30; source msha-controller-operator-history
- **operator_operates_mine:** Big River Materials, Inc. → Duffield Holdings Materials; 2009-12-01 to 2024-11-17; source msha-controller-operator-history
- **controller_controls_mine:** Ronald  Duffield → Duffield Holdings Materials; 2009-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ronald  Duffield → Big River Materials, Inc.; 2009-12-01 to 2024-11-17; source msha-controller-operator-history
- **operator_operates_mine:** Duffield Holdings, LLP → Duffield Holdings Materials; 2024-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David D.  Duffield → Duffield Holdings Materials; 2024-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David D.  Duffield → Duffield Holdings, LLP; 2024-11-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Luke B.  Duffield → Duffield Holdings, LLP; 2024-11-18 to current/open; source msha-controller-operator-history