# Relationship history for MSHA mine 2700478

Current hierarchy: **Trevor  Presby; Thaddeus  Presby → Presby Construction Inc. → Extec Robotrac Portable Screen**

- 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:** David W  Presby et al → Extec Robotrac Portable Screen; 2006-07-19 to 2014-01-31; source msha-controller-operator-history
- **controller_controls_mine:** Thaddeus  Presby et al → Extec Robotrac Portable Screen; 2014-02-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Presby Construction Inc. → Extec Robotrac Portable Screen; 2014-02-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David W  Presby et al → Presby Construction Inc.; 2014-02-05 to 2014-01-31; source msha-controller-operator-history
- **controller_controls_operator:** Thaddeus  Presby et al → Presby Construction Inc.; 2014-02-05 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Trevor  Presby et al → Presby Construction Inc.; 2014-02-05 to current/open; source msha-controller-operator-history