# Relationship history for MSHA mine 1700240

Current hierarchy: **Elementia Materiales → Dragon Products Company → Presque Isle**

- 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:** Trombley Redi-Mix Inc → Presque Isle; 1950-01-01 to 1985-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Trombley Redi-Mix Inc → Presque Isle; 1950-01-01 to 1985-08-14; source msha-controller-operator-history
- **controller_controls_operator:** Trombley Redi-Mix Inc → Trombley Redi-Mix Inc; 1950-01-01 to 1985-08-14; source msha-controller-operator-history
- **controller_controls_mine:** Passamaquoddy Tribe → Presque Isle; 1985-03-04 to 1988-10-03; source msha-controller-operator-history
- **operator_operates_mine:** Dragon Products Company → Presque Isle; 1985-08-15 to 1988-10-03; source msha-controller-operator-history
- **controller_controls_operator:** Passamaquoddy Tribe → Dragon Products Company; 1985-08-15 to 1988-10-03; source msha-controller-operator-history
- **controller_controls_mine:** C D N - USA → Presque Isle; 1988-10-01 to 2007-02-26; source msha-controller-operator-history
- **operator_operates_mine:** Dragon Products Company → Presque Isle; 1988-10-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** C D N - USA → Dragon Products Company; 1988-10-04 to 2007-02-26; source msha-controller-operator-history
- **controller_controls_mine:** Cementos Portland Valderrivas S A → Presque Isle; 2007-02-27 to 2016-10-25; source msha-controller-operator-history
- **controller_controls_operator:** Cementos Portland Valderrivas S A → Dragon Products Company; 2007-02-27 to 2016-10-25; source msha-controller-operator-history
- **controller_controls_mine:** Elementia Materiales → Presque Isle; 2016-10-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Elementia Materiales → Dragon Products Company; 2016-10-26 to current/open; source msha-controller-operator-history