# Relationship history for MSHA mine 1200652

Current hierarchy: **Barney C  Beer → Elkhart County Gravel, Inc. → Milford Plant**

- 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:** Zimmerman Gravel → Milford Plant; 1950-01-01 to 1991-11-06; source msha-controller-operator-history
- **controller_controls_mine:** Elmer  Zimmerman → Milford Plant; 1950-01-01 to 1991-11-06; source msha-controller-operator-history
- **controller_controls_operator:** Elmer  Zimmerman → Zimmerman Gravel; 1950-01-01 to 1991-11-06; source msha-controller-operator-history
- **controller_controls_mine:** Barney C  Beer  et al → Milford Plant; 1981-09-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Zimmerman Newcomer Gravel → Milford Plant; 1991-11-07 to 2018-04-29; source msha-controller-operator-history
- **controller_controls_mine:** Gary  Newcomer → Milford Plant; 1991-11-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Gary  Newcomer → Zimmerman Newcomer Gravel; 1991-11-07 to 2018-04-29; source msha-controller-operator-history
- **operator_operates_mine:** Elkhart County Gravel, Inc. → Milford Plant; 2018-04-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barney C  Beer  et al → Elkhart County Gravel, Inc.; 2018-04-30 to current/open; source msha-controller-operator-history