# Relationship history for MSHA mine 4300639

Current hierarchy: **Eric C  Boyden → J.A. McDonald, Inc. → 1989 Thunderbird Jaw**

- 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

- **controller_controls_mine:** James A  McDonald → 1989 Thunderbird Jaw; 2001-11-06 to 2012-12-31; source msha-controller-operator-history
- **operator_operates_mine:** J.A. McDonald, Inc. → 1989 Thunderbird Jaw; 2005-10-18 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** James A  McDonald → J.A. McDonald, Inc.; 2005-10-18 to 2012-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Eric C  Boyden → 1989 Thunderbird Jaw; 2013-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Eric C  Boyden → J.A. McDonald, Inc.; 2013-01-01 to current/open; source msha-controller-operator-history