# Relationship history for MSHA mine 2602467

Current hierarchy: **Alex K  Bernhard → Al's Excavating & Grading Inc → CARSON QUARRY PROD**

- 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:** Al'S Plumbing & Heating Inc → CARSON QUARRY PROD; 2001-09-01 to 2008-04-07; source msha-controller-operator-history
- **controller_controls_mine:** Alex K  Bernhard → CARSON QUARRY PROD; 2001-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alex K  Bernhard → Al'S Plumbing & Heating Inc; 2001-09-01 to 2008-04-07; source msha-controller-operator-history
- **operator_operates_mine:** Al's Excavating & Grading Inc → CARSON QUARRY PROD; 2008-04-08 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Alex K  Bernhard → CARSON QUARRY PROD; 2008-04-08 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Alex K  Bernhard → Al's Excavating & Grading Inc; 2008-04-08 to current/open; source msha-controller-operator-history