# Relationship history for MSHA mine 0502267

Current hierarchy: **Risk Robert → Leadville Corp → Stringtown 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

- **controller_controls_mine:** Hecla Mining Company → Stringtown Mill; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Day Mines Inc → Stringtown Mill; 1950-01-01 to 1981-10-19; source msha-controller-operator-history
- **controller_controls_mine:** Day Mines Inc → Stringtown Mill; 1950-01-01 to 1981-11-22; source msha-controller-operator-history
- **controller_controls_operator:** Day Mines Inc → Day Mines Inc; 1950-01-01 to 1981-10-19; source msha-controller-operator-history
- **operator_operates_mine:** Hecla Mining Company → Stringtown Mill; 1981-10-20 to 1987-04-30; source msha-controller-operator-history
- **controller_controls_operator:** Hecla Mining Company → Hecla Mining Company; 1981-10-20 to 1987-04-30; source msha-controller-operator-history
- **controller_controls_mine:** Risk Robert → Stringtown Mill; 1983-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Leadville Corp → Stringtown Mill; 1987-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Risk Robert → Leadville Corp; 1987-05-01 to current/open; source msha-controller-operator-history