# Relationship history for MSHA mine 4608099

Current hierarchy: **Porter Mike → Associated Contractors & Trucking Inc → Otter Creek Drag**

- 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:** Associated Contractors & Trucking Inc → Otter Creek Drag; 1991-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Porter Mike → Otter Creek Drag; 1991-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Porter Mike → Associated Contractors & Trucking Inc; 1991-09-01 to current/open; source msha-controller-operator-history