# Relationship history for MSHA mine 4201979

Current hierarchy: **Neson David → Interstate Gold & Gas → Silver Streak 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

- **operator_operates_mine:** Interstate Gold & Gas → Silver Streak Mine; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Neson David → Silver Streak Mine; 1986-05-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Neson David → Interstate Gold & Gas; 1986-05-01 to current/open; source msha-controller-operator-history