# Relationship history for MSHA mine 4503034

Current hierarchy: **Mountain Minerals Company Ltd → Mountain Minerals Northwest Company Ltd → Sheep Creek 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

- **operator_operates_mine:** Phoenix Resource Recovery Company Inc → Sheep Creek Mill; 1985-03-01 to 1987-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Phoenix Resource Recovery Company Inc → Sheep Creek Mill; 1985-03-01 to 1987-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Phoenix Resource Recovery Company Inc → Phoenix Resource Recovery Company Inc; 1985-03-01 to 1987-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Northport Mill-Jv → Sheep Creek Mill; 1988-01-01 to 1991-05-20; source msha-controller-operator-history
- **controller_controls_mine:** Silver Bell Inc & Firegold Corp → Sheep Creek Mill; 1988-01-01 to 1991-05-20; source msha-controller-operator-history
- **controller_controls_operator:** Silver Bell Inc & Firegold Corp → Northport Mill-Jv; 1988-01-01 to 1991-05-20; source msha-controller-operator-history
- **operator_operates_mine:** Newco → Sheep Creek Mill; 1991-05-21 to 1991-07-24; source msha-controller-operator-history
- **controller_controls_mine:** Matovich Al → Sheep Creek Mill; 1991-05-21 to 1991-07-24; source msha-controller-operator-history
- **controller_controls_operator:** Matovich Al → Newco; 1991-05-21 to 1991-07-24; source msha-controller-operator-history
- **operator_operates_mine:** Mountain Minerals Northwest Company Ltd → Sheep Creek Mill; 1991-07-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Mountain Minerals Company Ltd → Sheep Creek Mill; 1991-07-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Mountain Minerals Company Ltd → Mountain Minerals Northwest Company Ltd; 1991-07-25 to current/open; source msha-controller-operator-history