# Relationship history for MSHA mine 0503123

Current hierarchy: **Energy Resources Investment Corp → Quadra Mining & Development Company → Lazy L**

- 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:** Brooks Minerals Inc → Lazy L; 1950-01-01 to 1979-11-14; source msha-controller-operator-history
- **controller_controls_mine:** Brooks Fred H → Lazy L; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Brooks Fred H → Brooks Minerals Inc; 1950-01-01 to 1979-11-14; source msha-controller-operator-history
- **operator_operates_mine:** Quadra Mining & Development Company → Lazy L; 1979-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Energy Resources Investment Corp → Lazy L; 1979-11-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Energy Resources Investment Corp → Quadra Mining & Development Company; 1979-11-15 to current/open; source msha-controller-operator-history