# Relationship history for MSHA mine 1000526

Current hierarchy: **Barrett R M → R M Barrett → Salmon River Scheelite 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:** Salmon River Scheelite Corp → Salmon River Scheelite Mill; 1950-01-01 to 1978-08-30; source msha-controller-operator-history
- **controller_controls_mine:** Salmon River Scheelite Corp → Salmon River Scheelite Mill; 1950-01-01 to 1978-08-30; source msha-controller-operator-history
- **controller_controls_operator:** Salmon River Scheelite Corp → Salmon River Scheelite Corp; 1950-01-01 to 1978-08-30; source msha-controller-operator-history
- **operator_operates_mine:** R M Barrett → Salmon River Scheelite Mill; 1978-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Barrett R M → Salmon River Scheelite Mill; 1978-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Barrett R M → R M Barrett; 1978-08-31 to current/open; source msha-controller-operator-history