# Relationship history for MSHA mine 3304794

Current hierarchy: **Ross David Duff; Lauren R Duff-Major → Duff Sand and Gravel Inc. → DSG #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:** Duff Sand and Gravel Inc. → DSG #1; 2023-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Lauren R Duff-Major et al → DSG #1; 2023-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lauren R Duff-Major et al → Duff Sand and Gravel Inc.; 2023-04-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ross David Duff et al → Duff Sand and Gravel Inc.; 2023-04-05 to current/open; source msha-controller-operator-history