# Relationship history for MSHA mine 1901060

Current hierarchy: **Christopher  Dauphinais → DAUPHINAIS CONCRETE → N Brookfield Plant**

- 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:** F T Smith Sand & Gravel Co → N Brookfield Plant; 1998-07-01 to 2026-05-31; source msha-controller-operator-history
- **controller_controls_mine:** Frederick T  Smith → N Brookfield Plant; 1998-07-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Frederick T  Smith → F T Smith Sand & Gravel Co; 1998-07-01 to 2026-05-31; source msha-controller-operator-history
- **operator_operates_mine:** DAUPHINAIS CONCRETE → N Brookfield Plant; 2026-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Christopher  Dauphinais → N Brookfield Plant; 2026-06-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Christopher  Dauphinais → DAUPHINAIS CONCRETE; 2026-06-01 to current/open; source msha-controller-operator-history