# Relationship history for MSHA mine 4503765

Current hierarchy: **John  Brumfield → Brumfield Construction, Inc. → Portable 1**

- 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:** Brumfield Construction, Inc. → Portable 1; 2017-03-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Brumfield → Portable 1; 2017-03-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Brumfield → Brumfield Construction, Inc.; 2017-03-13 to current/open; source msha-controller-operator-history