# Relationship history for MSHA mine 0302082

Current hierarchy: **Matt  Duffield; Luke B Duffield; David D Duffield → Ronnie Duffield Gravel Company → Alexander Quarry**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Ronald  Duffield → Alexander Quarry; 1950-01-01 to 2020-06-07; source msha-controller-operator-history
- **controller_controls_mine:** David D Duffield et al → Alexander Quarry; 2020-06-08 to 2022-06-02; source msha-controller-operator-history
- **operator_operates_mine:** Ronnie Duffield Gravel Company → Alexander Quarry; 2022-05-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David D Duffield et al → Ronnie Duffield Gravel Company; 2022-05-20 to 2022-06-02; source msha-controller-operator-history
- **controller_controls_operator:** Luke B Duffield et al → Ronnie Duffield Gravel Company; 2022-05-20 to 2022-06-02; source msha-controller-operator-history
- **controller_controls_operator:** Ronald M Duffield et al → Ronnie Duffield Gravel Company; 2022-05-20 to 2022-06-02; source msha-controller-operator-history
- **controller_controls_operator:** Ronald  Duffield → Ronnie Duffield Gravel Company; 2022-05-20 to 2020-06-07; source msha-controller-operator-history
- **controller_controls_mine:** Luke B Duffield et al → Alexander Quarry; 2022-06-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Luke B Duffield et al → Ronnie Duffield Gravel Company; 2022-06-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David D Duffield et al → Ronnie Duffield Gravel Company; 2022-06-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Matt  Duffield et al → Ronnie Duffield Gravel Company; 2022-06-03 to current/open; source msha-controller-operator-history