# Relationship history for MSHA mine 3503303

Current hierarchy: **Rogers Northwest Inc → Tigard Sand & Gravel LLC → 115 Portable**

- 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:** A J  Urbanek → 115 Portable; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Circle Construction Company → 115 Portable; 1988-03-01 to 2004-11-29; source msha-controller-operator-history
- **controller_controls_operator:** A J  Urbanek → Circle Construction Company; 1988-03-01 to 2004-11-29; source msha-controller-operator-history
- **operator_operates_mine:** Tigard Sand & Gravel LLC → 115 Portable; 2004-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** A J  Urbanek → 115 Portable; 2004-11-30 to 2025-04-06; source msha-controller-operator-history
- **controller_controls_operator:** A J  Urbanek → Tigard Sand & Gravel LLC; 2004-11-30 to 2025-04-06; source msha-controller-operator-history
- **controller_controls_mine:** Rogers Northwest Inc → 115 Portable; 2025-04-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Rogers Northwest Inc → Tigard Sand & Gravel LLC; 2025-04-07 to current/open; source msha-controller-operator-history