# Relationship history for MSHA mine 2602004

Current hierarchy: **Holder Donald R → Bronco Minerals Inc → Golden Sands Project**

- 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:** Gravcon Inc → Golden Sands Project; 1987-04-01 to 1988-04-14; source msha-controller-operator-history
- **controller_controls_mine:** Riggs Leland → Golden Sands Project; 1987-04-01 to 1988-04-14; source msha-controller-operator-history
- **controller_controls_operator:** Riggs Leland → Gravcon Inc; 1987-04-01 to 1988-04-14; source msha-controller-operator-history
- **operator_operates_mine:** Bronco Minerals Inc → Golden Sands Project; 1988-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Holder Donald R → Golden Sands Project; 1988-04-15 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Holder Donald R → Bronco Minerals Inc; 1988-04-15 to current/open; source msha-controller-operator-history