# Relationship history for MSHA mine 0504992

Current hierarchy: **Steven  Craig; Nick  Michael → Union Milling Contractors, LLC → Leadville Mill**

- 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:** Union Milling Company → Leadville Mill; 2012-06-22 to 2021-05-12; source msha-controller-operator-history
- **controller_controls_mine:** Denver Equity Corp et al → Leadville Mill; 2012-06-22 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Denver Equity Corp et al → Union Milling Company; 2012-06-22 to 2021-05-12; source msha-controller-operator-history
- **controller_controls_operator:** SNH Investments LLC et al → Union Milling Company; 2012-06-22 to 2021-05-12; source msha-controller-operator-history
- **operator_operates_mine:** Union Milling Contractors, LLC → Leadville Mill; 2021-05-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Nick  Michael et al → Leadville Mill; 2021-05-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Nick  Michael et al → Union Milling Contractors, LLC; 2021-05-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Steven  Craig et al → Union Milling Contractors, LLC; 2021-05-13 to current/open; source msha-controller-operator-history