# Relationship history for MSHA mine 0600272

Current hierarchy: **Carl J  Clemente → 21st Century Concrete Inc → CENTURY ACQUISITIONS**

- 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:** Connecticut Sand & Stone Corp → CENTURY ACQUISITIONS; 1950-01-01 to 2001-05-13; source msha-controller-operator-history
- **controller_controls_mine:** Roger L  Toffolon → CENTURY ACQUISITIONS; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Roger L  Toffolon → Connecticut Sand & Stone Corp; 1950-01-01 to 2001-05-13; source msha-controller-operator-history
- **operator_operates_mine:** 21st Century Concrete Inc → CENTURY ACQUISITIONS; 2001-05-14 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Carl J  Clemente  et al → CENTURY ACQUISITIONS; 2001-05-14 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Carl J  Clemente  et al → 21st Century Concrete Inc; 2001-05-14 to current/open; source msha-controller-operator-history