# Relationship history for MSHA mine 1202121

Current hierarchy: **Barney C  Beer → Elkhart County Gravel Inc → PORTABLE PLANT II**

- 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:** Barney C  Beer  et al → PORTABLE PLANT II; 1981-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Elkhart County Gravel Inc → PORTABLE PLANT II; 1992-03-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barney C  Beer  et al → Elkhart County Gravel Inc; 1992-03-01 to current/open; source msha-controller-operator-history