# Relationship history for MSHA mine 4607574

Current hierarchy: **Short Denver Jr → D Short Coal Company Inc → Blizzard Run Mine**

- 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:** Delta Industries Inc → Blizzard Run Mine; 1972-12-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Short Denver Jr → Blizzard Run Mine; 1985-02-22 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Delta Mining Inc → Blizzard Run Mine; 1988-08-01 to 1989-04-24; source msha-controller-operator-history
- **controller_controls_operator:** Delta Industries Inc → Delta Mining Inc; 1988-08-01 to 1989-04-24; source msha-controller-operator-history
- **operator_operates_mine:** Tinnelco Inc → Blizzard Run Mine; 1989-04-25 to 1989-10-23; source msha-controller-operator-history
- **controller_controls_mine:** Tinnel Nelson → Blizzard Run Mine; 1989-04-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Tinnel Nelson → Tinnelco Inc; 1989-04-25 to 1989-10-23; source msha-controller-operator-history
- **operator_operates_mine:** D Short Coal Company Inc → Blizzard Run Mine; 1989-10-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Short Denver Jr → D Short Coal Company Inc; 1989-10-24 to current/open; source msha-controller-operator-history