# Relationship history for MSHA mine 2901892

Current hierarchy: **Nicor Minerals Inc → Nicor Mineral Ventures Inc → Iron King-Lone Star Group**

- 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:** Nicor Mineral Ventures Inc → Iron King-Lone Star Group; 1982-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nicor Minerals Inc → Iron King-Lone Star Group; 1982-11-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nicor Minerals Inc → Nicor Mineral Ventures Inc; 1982-11-01 to current/open; source msha-controller-operator-history