# Relationship history for MSHA mine 0503609

Current hierarchy: **Smith A K → Leadville Silver & Gold Inc → St Kevin**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** Norton William B → St Kevin; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Norsigo Processing & Refining Ltd → St Kevin; 1980-11-01 to 1983-06-23; source msha-controller-operator-history
- **controller_controls_operator:** Norton William B → Norsigo Processing & Refining Ltd; 1980-11-01 to 1983-06-23; source msha-controller-operator-history
- **controller_controls_mine:** Windsor Resources Inc → St Kevin; 1983-06-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Windsor Resources (Us) Ltd → St Kevin; 1983-06-24 to 1987-10-11; source msha-controller-operator-history
- **controller_controls_operator:** Windsor Resources Inc → Windsor Resources (Us) Ltd; 1983-06-24 to 1987-10-11; source msha-controller-operator-history
- **operator_operates_mine:** Leadville Silver & Gold Inc → St Kevin; 1987-10-12 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Smith A K → St Kevin; 1987-10-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Smith A K → Leadville Silver & Gold Inc; 1987-10-12 to current/open; source msha-controller-operator-history