# Relationship history for MSHA mine 0404768

Current hierarchy: **Yuba Natural Resources Inc → Yuba Silica Inc → Yuba Silica**

- 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:** Yuba Silica → Yuba Silica; 1985-09-01 to 1988-02-23; source msha-controller-operator-history
- **controller_controls_mine:** Yuba Natural Resources Inc & G K Ventures Inc → Yuba Silica; 1985-09-01 to 1988-02-23; source msha-controller-operator-history
- **controller_controls_operator:** Yuba Natural Resources Inc & G K Ventures Inc → Yuba Silica; 1985-09-01 to 1988-02-23; source msha-controller-operator-history
- **operator_operates_mine:** Yuba Silica Inc → Yuba Silica; 1988-02-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Yuba Natural Resources Inc → Yuba Silica; 1988-02-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Yuba Natural Resources Inc → Yuba Silica Inc; 1988-02-24 to current/open; source msha-controller-operator-history