# Relationship history for MSHA mine 2602225

Current hierarchy: **William  Blattner Jr → D H Blattner & Sons Inc → Aurora Partnership**

- 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:** Helms Robert L Construction & Development Co → Aurora Partnership; 1986-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** William  Blattner Jr → Aurora Partnership; 1989-06-14 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lost Dutchman Construction Inc → Aurora Partnership; 1993-03-01 to 1993-08-31; source msha-controller-operator-history
- **controller_controls_operator:** Helms Robert L Construction & Development Co → Lost Dutchman Construction Inc; 1993-03-01 to 1993-08-31; source msha-controller-operator-history
- **operator_operates_mine:** D H Blattner & Sons Inc → Aurora Partnership; 1993-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** William  Blattner Jr → D H Blattner & Sons Inc; 1993-09-01 to current/open; source msha-controller-operator-history