# Relationship history for MSHA mine 1900287

Current hierarchy: **Leo Concrete Service Inc → CHICOPEE CONCRETE SERVICE INCORPORTED → SOUTH HADLEY PIT**

- 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:** Chicopee Concrete Service Incorported → SOUTH HADLEY PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Leo Concrete Service Inc → SOUTH HADLEY PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Leo Concrete Service Inc → Chicopee Concrete Service Incorported; 1950-01-01 to current/open; source msha-controller-operator-history