# Relationship history for MSHA mine 2002942

Current hierarchy: **Daniel R  Balkema; Ralph T  Balkema → Aggregate Resources, Inc. → Midway Pit**

- 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:** Daniel R  Balkema et al → Midway Pit; 1989-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Balkema Excavating Inc → Midway Pit; 1994-10-01 to 2002-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Daniel R  Balkema et al → Balkema Excavating Inc; 1994-10-01 to 2002-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Ralph T  Balkema et al → Balkema Excavating Inc; 1994-10-01 to 2002-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Daniel R  Balkema et al → Midway Pit; 2002-01-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Aggregate Resources, Inc. → Midway Pit; 2003-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Daniel R  Balkema et al → Aggregate Resources, Inc.; 2003-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ralph T  Balkema et al → Aggregate Resources, Inc.; 2003-01-01 to current/open; source msha-controller-operator-history