# Relationship history for MSHA mine 0404052

Current hierarchy: **Ralph  Miller → Miller'S Backhoe & Excavating → Blue Lake Pit And Mill**

- 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:** Artron Enterprises Inc → Blue Lake Pit And Mill; 1950-01-01 to 1985-05-15; source msha-controller-operator-history
- **controller_controls_mine:** Harnden Art → Blue Lake Pit And Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harnden Art → Artron Enterprises Inc; 1950-01-01 to 1985-05-15; source msha-controller-operator-history
- **operator_operates_mine:** Miller'S Backhoe & Excavating → Blue Lake Pit And Mill; 1985-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ralph  Miller → Blue Lake Pit And Mill; 1985-05-16 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ralph  Miller → Miller'S Backhoe & Excavating; 1985-05-16 to current/open; source msha-controller-operator-history