# Relationship history for MSHA mine 4503203

Current hierarchy: **Dennis  Scheffer → Sumas Transport 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

- **controller_controls_mine:** Dennis  Scheffer → Portable #1; 1979-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Eddie Markham Trucking → Portable #1; 1989-01-01 to 1998-12-14; source msha-controller-operator-history
- **controller_controls_mine:** Eddie  Markham → Portable #1; 1989-01-01 to 1998-12-14; source msha-controller-operator-history
- **controller_controls_operator:** Eddie  Markham → Eddie Markham Trucking; 1989-01-01 to 1998-12-14; source msha-controller-operator-history
- **operator_operates_mine:** Sumas Transport Inc → Portable #1; 1998-12-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dennis  Scheffer → Sumas Transport Inc; 1998-12-15 to current/open; source msha-controller-operator-history