# Relationship history for MSHA mine 1900279

Current hierarchy: **Stephen A  Cardi → Westport Stone & Sand Corp → Westport Stone & Sand Corporation**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Westport Sand & Gravel Corp → Westport Stone & Sand Corporation; 1950-01-01 to 1991-12-06; source msha-controller-operator-history
- **controller_controls_mine:** Jeffrey A  Douglass  et al → Westport Stone & Sand Corporation; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Jeffrey A  Douglass  et al → Westport Sand & Gravel Corp; 1950-01-01 to 1991-12-06; source msha-controller-operator-history
- **operator_operates_mine:** Westport Stone & Sand Corp → Westport Stone & Sand Corporation; 1991-12-07 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Stephen A  Cardi  et al → Westport Stone & Sand Corporation; 1991-12-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Stephen A  Cardi  et al → Westport Stone & Sand Corp; 1991-12-07 to current/open; source msha-controller-operator-history