# Relationship history for MSHA mine 3304163

Current hierarchy: **James D  Duff; James S  Duff → C E Duff & Son Inc → Portable Plant #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

- **controller_controls_mine:** James E  Duff → Portable Plant #1; 1950-01-01 to 2014-09-22; source msha-controller-operator-history
- **operator_operates_mine:** C E Duff & Son Inc → Portable Plant #1; 1989-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James E  Duff → C E Duff & Son Inc; 1989-05-01 to 2014-09-22; source msha-controller-operator-history
- **controller_controls_mine:** James S  Duff et al → Portable Plant #1; 2014-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James S  Duff et al → C E Duff & Son Inc; 2014-09-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James D  Duff et al → C E Duff & Son Inc; 2014-09-23 to current/open; source msha-controller-operator-history