# Relationship history for MSHA mine 4404826

Current hierarchy: **Chamberlain Leslie A → Chamberlain Grading & Excavating Corp → No 1 Surface**

- 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:** Euramco Ltd → No 1 Surface; 1977-07-01 to 1977-08-23; source msha-controller-operator-history
- **controller_controls_mine:** De Beaubien Philip F Jr → No 1 Surface; 1977-07-01 to 1978-09-27; source msha-controller-operator-history
- **controller_controls_operator:** De Beaubien Philip F Jr → Euramco Ltd; 1977-07-01 to 1977-08-23; source msha-controller-operator-history
- **operator_operates_mine:** Chamberlain Grading & Excavating Corp → No 1 Surface; 1977-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Chamberlain Leslie A → No 1 Surface; 1977-08-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Chamberlain Leslie A → Chamberlain Grading & Excavating Corp; 1977-08-24 to current/open; source msha-controller-operator-history